This dissertation considers whether photography as a language translates a transient moment into an embodied image. This is considered to be a mimesis of the moment as an aid for memory. By following a dialectic approach I posit a thesis based on the common sense perception of photography which states that photography is an artefactual mimesis aiding memory. After reflecting on Plato’s concept of writing as a pharmakon and Jacques Derrida’s deconstruction theory I establish an antithesis which proclaims that a photograph aids memory but also leads to the illusion of remembering past experiences. The synthesis is then presented which resolves the opposing ideas. This component argues that a photograph is a mimetic device that aids memory by presenting embodied fragmented reflections of time which can be used to create new meanings and memories. The dissertation concludes with a discussion that supports and integrates this argument with visual research. / Art History, Visual Arts and Musicology / M.A. (Visual Arts)

Les lésions de la moelle épinière ont un impact significatif sur la qualité de la vie car elles peuvent induire des déficits moteurs (paralysie) et sensoriels. Ces déficits évoluent dans le temps à mesure que le système nerveux central se réorganise, en impliquant des mécanismes physiologiques et neurochimiques encore mal connus. L'ampleur de ces déficits ainsi que le processus de réhabilitation dépendent fortement des voies anatomiques qui ont été altérées dans la moelle épinière. Il est donc crucial de pouvoir attester l'intégrité de la matière blanche après une lésion spinale et évaluer quantitativement l'état fonctionnel des neurones spinaux. Un grand intérêt de l'imagerie par résonance magnétique (IRM) est qu'elle permet d'imager de façon non invasive les propriétés fonctionnelles et anatomiques du système nerveux central. Le premier objectif de ce projet de thèse a été de développer l'IRM de diffusion afin d'évaluer l'intégrité des axones de la matière blanche après une lésion médullaire. Le deuxième objectif a été d'évaluer dans quelle mesure l'IRM fonctionnelle permet de mesurer l'activité des neurones de la moelle épinière. Bien que largement appliquées au cerveau, l'IRM de diffusion et l'IRM fonctionnelle de la moelle épinière sont plus problématiques. Les difficultés associées à l'IRM de la moelle épinière relèvent de sa fine géométrie (environ 1 cm de diamètre chez l'humain), de la présence de mouvements d'origine physiologique (cardiaques et respiratoires) et de la présence d'artefacts de susceptibilité magnétique induits par les inhomogénéités de champ, notamment au niveau des disques intervertébraux et des poumons. L'objectif principal de cette thèse a donc été de développer des méthodes permettant de contourner ces difficultés. Ce développement a notamment reposé sur l'optimisation des paramètres d'acquisition d'images anatomiques, d'images pondérées en diffusion et de données fonctionnelles chez le chat et chez l'humain sur un IRM à 3 Tesla. En outre, diverses stratégies ont été étudiées afin de corriger les distorsions d'images induites par les artefacts de susceptibilité magnétique, et une étude a été menée sur la sensibilité et la spécificité de l'IRM fonctionnelle de la moelle épinière. Les résultats de ces études démontrent la faisabilité d'acquérir des images pondérées en diffusion de haute qualité, et d'évaluer l'intégrité de voies spinales spécifiques après lésion complète et partielle. De plus, l'activité des neurones spinaux a pu être détectée par IRM fonctionnelle chez des chats anesthésiés. Bien qu'encourageants, ces résultats mettent en lumière la nécessité de développer davantage ces nouvelles techniques. L'existence d'un outil de neuroimagerie fiable et robuste, capable de confirmer les paramètres cliniques, permettrait d'améliorer le diagnostic et le pronostic chez les patients atteints de lésions médullaires. Un des enjeux majeurs serait de suivre et de valider l'effet de diverses stratégies thérapeutiques. De telles outils représentent un espoir immense pour nombre de personnes souffrant de traumatismes et de maladies neurodégénératives telles que les lésions de la moelle épinière, les tumeurs spinales, la sclérose en plaques et la sclérose latérale amyotrophique. / Spinal cord injury has a significant impact on quality of life since it can lead to motor (paralysis) and sensory deficits. These deficits evolve in time as reorganisation of the central nervous system occurs, involving physiological and neurochemical mechanisms that are still not fully understood. Given that both the severity of the deficit and the successful rehabilitation process depend on the anatomical pathways that have been altered in the spinal cord, it may be of great interest to assess white matter integrity after a spinal lesion and to evaluate quantitatively the functional state of spinal neurons. The great potential of magnetic resonance imaging (MRI) lies in its ability to investigate both anatomical and functional properties of the central nervous system non invasively. To address the problem of spinal cord injury, this project aimed to evaluate the benefits of diffusion-weighted MRI to assess the integrity of white matter axons that remain after spinal cord injury. The second objective was to evaluate to what extent functional MRI can measure the activity of neurons in the spinal cord. Although widely applied to the brain, diffusion-weighted MRI and functional MRI of the spinal cord are not straightforward. Various issues arise from the small cross-section width of the cord, the presence of cardiac and respiratory motions, and from magnetic field inhomogeneities in the spinal region. The main purpose of the present thesis was therefore to develop methodologies to circumvent these issues. This development notably focused on the optimization of acquisition parameters to image anatomical, diffusion-weighted and functional data in cats and humans at 3T using standard coils and pulse sequences. Moreover, various strategies to correct for susceptibility-induced distortions were investigated and the sensitivity and specificity in spinal cord functional MRI was studied. As a result, acquisition of high spatial and angular diffusion-weighted images and evaluation of the integrity of specific spinal pathways following spinal cord injury was achieved. Moreover, functional activations in the spinal cord of anaesthetized cats was detected. Although encouraging, these results highlight the need for further technical and methodological development in the near-future. Being able to develop a reliable neuroimaging tool for confirming clinical parameters would improve diagnostic and prognosis. It would also enable to monitor the effect of various therapeutic strategies. This would certainly bring hope to a large number of people suffering from trauma and neurodegenerative diseases such as spinal cord injury, tumours, multiple sclerosis and amyotrophic lateral sclerosis.

There is a increasing number of enrolled students in higher education, which leads toless personal time with the teachers, and therefore supplementary technologies needs to takeplace. This paper investigate how Testbased learning with feedback affects the learningoutcomes in a group of students, by measuring their perceived value. The research also investigateswhat design principles to follow, when working with E-learning and Testbasedlearning with feedback. For this this research an IT-artefact will be created which the studentwill be able to use as a practice tool. With the IT-artefact they will be able to answera number of question, in a subject, and get personalized feedback depending on their score.The quantitative research will then evaluate whether the students perceived thoughts aboutthe IT-artifact and the learning method itself. The result shows eight design principles onhow to design an E-learning tool where student should learn through Test based learningwith feedback. The result also indicates that the perceived feeling of learning is good eventhough a big number of respondents never participated in the survey. / Antalet studenter på Universiteten växer ständigt. Detta leder till minskad relationmed lärare och för att upprätthålla kvalite behövs andra lösningar. En sådan lösning äre-läromedel som bygger på testbaserat lärande med feedback. Arbetet undersöker vilka designprincipersom ska följas när man utvecklar ett E-lärmomedel med testbaserat lärandeoch feedback. För undersökningen kommer en IT-artefakt att skapas där studenter kan testasina kunskaper på ett ämne för lärande syfte. De besvarar ett antal frågor, och beroende påderas resultat får de tillbaka personlig feedback. Den kvantitativa undersökningen kommersedan att analysera studenternas uppfattning av IT-artefakten som hjälpmedel. Resultatetbeskriver åtta olika designprinciper för hur man ska designa ett E-läroverktyg där studenterska kunna testa sina kunskaper. Resultatet tillsammans med tidigare forskning tyder ävenpå en uppfattad känsla av ökad inlärning.

La profession de designer n'est pas toujours bien identifiée dans le monde du travail et les designers ont eux-mêmes des difficultés à expliquer en quoi consiste leur activité. La recherche en design n'a en fait pas d'assise théorique clairement établie et le premier objectif de cette thèse est de mettre en lumière les zones d'ombre qui règnent en son sein. Notre second objectif est d'élaborer un cadre d'analyse permettant d'apporter un nouvel éclairage sur le design. Le design étant une activité effectuée par un praticien réflexif, l'approche praxéologique invite à construire un discours permettant de décrire cette activité, quel que soit le domaine d'application concerné. Cette activité se décline donc selon deux plans : celui de l'action réflexive et celui de l'action pratique (qui porte sur le monde réel), l'une étant intrinsèquement liée à l'autre par des processus que nous qualifions de transducteurs. C'est la terre du réalisable, qui se trouve à la croisée du monde réflexif et du monde réel, que le designer explore. Celui-ci n'est par ailleurs pas le seul agent à intervenir lors du processus de création : identifier clairement son rôle au sein de cette organisation est donc nécessaire. Un designer occupe une position pivot au sein de cette organisation, il est amené à adopter différents points de vue entre eux, qu'ils articulent entre eux de manière à pouvoir voir l'entité réelle qui est à la croisée des regards. Un des défis de la recherche en design est alors non seulement de s'affirmer en tant que discipline à part entière, mais aussi de montrer qu'appréhender des problèmes de design permet de développer une manière de penser complexe et transdisciplinaire.

<p>This thesis rewievs present day research on the settlement of Östra Aros in central Sweden. The thesis deals with the period from late Iron age to about 1270 AD, when the Swedish archdiocese moved to the already existing early-medieval settlement of Östra Aros, thus becoming the medieval town of Uppsala. The basis of the thesis is the study of a variety of source materials, such as artefact studies, runestones, topography and the prehistoric and early medieval hinterland. The thesis centers on archaeological excavation data and dating of settlement structures, particularly focusing on the settlements establishment. Through a critical review of primarily the written record and the archaeological data, the settlements characteristics and functions are discussed, emphasising when and if the settlement could be described as a town, central- or trading place.</p>

Mechanomyography (MMG) has been proposed as a control modality for alternative access technologies for individuals with disabilities. However, MMG recordings are highly susceptible to contamination from limb movements. Pressure-based transducers are touted to be the most robust to external movement although there is some debate about their optimal chamber geometry, in terms of low frequency gain and spectral flatness. To investigate the question of preferred geometry, transducers with varying chamber shapes were designed, manufactured and tested. The best performance was achieved with a transducer consisting of a low-frequency MEMS microphone, a 4 micron thick aluminized mylar membrane and a rigid conical chamber 7 mm in diameter and 5 mm in height. Furthermore, microphone-derived MMG spectra were found to be less influenced by motion artifact than corresponding accelerometer-derived spectra. However, artifact harmonics were present in both spectra, suggesting that bandpass filtering may not remove artifact influences permeating into MMG frequency bands.

Mechanomyography (MMG) has been proposed as a control modality for alternative access technologies for individuals with disabilities. However, MMG recordings are highly susceptible to contamination from limb movements. Pressure-based transducers are touted to be the most robust to external movement although there is some debate about their optimal chamber geometry, in terms of low frequency gain and spectral flatness. To investigate the question of preferred geometry, transducers with varying chamber shapes were designed, manufactured and tested. The best performance was achieved with a transducer consisting of a low-frequency MEMS microphone, a 4 micron thick aluminized mylar membrane and a rigid conical chamber 7 mm in diameter and 5 mm in height. Furthermore, microphone-derived MMG spectra were found to be less influenced by motion artifact than corresponding accelerometer-derived spectra. However, artifact harmonics were present in both spectra, suggesting that bandpass filtering may not remove artifact influences permeating into MMG frequency bands.

In system identification scenario, the linear approximation of the system modelled by its impulse response, is estimated in real time by gradient type Least Mean Square (LMS) or Recursive Least Squares (RLS) algorithms. In recent applications like acoustic echo cancellation, the order of the impulse response to be estimated is very high, and these traditional approaches are inefficient and real time implementation becomes difficult. Alternatively, the system is modelled by a set of shorter adaptive filters operating in parallel on subsampled signals. This approach, referred to as subband adaptive filtering, is expected to reduce not only the computational complexity but also to improve the convergence rate of the adaptive algorithm. But in practice, different subband adaptive algorithms have to be used to enhance the performance with respect to complexity, convergence rate and processing delay. A single subband adaptive filtering algorithm which outperforms the full band scheme in all applications is yet to be realized. This thesis is intended to study the subband adaptive filtering techniques and explore the possibilities of better algorithms for performance improvement. Three different subband adaptive algorithms have been proposed and their performance have been verified through simulations. These algorithms have been applied to acoustic echo cancellation and EEG artefact minimization problems. Details of the work To start with, the fast FIR filtering scheme introduced by Mou and Duhamel has been generalized. The Perfect Reconstruction Filter Bank (PRFB) is used to model the linear FIR system. The structure offers efficient implementation with reduced arithmetic complexity. By using a PRFB with non adjacent filters non overlapping, many channel filters can be eliminated from the structure. This helps in reducing the complexity of the structure further, but introduces approximation in the model. The modelling error depends on the stop band attenuation of the filters of the PRFB. The error introduced due to approximation is tolerable for applications like acoustic echo cancellation. The filtered output of the modified generalized fast filtering structure is given by (formula) where, Pk(z) is the main channel output, Pk,, k+1 (z) is the output of auxiliary channel filters at the reduced rate, Gk (z) is the kth synthesis filter and M the number of channels in the PRFB. An adaptation scheme is developed for adapting the main channel filters. Auxiliary channel filters are derived from main channel filters. Secondly, the aliasing problem of the classical structure is reduced without using the cross filters. Aliasing components in the estimated signal results in very poor steady state performance in the classical structure. Attempts to eliminate the aliasing have reduced the computation gain margin and the convergence rate. Any attempt to estimate the subband reference signals from the aliased subband input signals results in aliasing. The analysis filter Hk(z) having the following antialiasing property (formula) can avoid aliasing in the input subband signal. The asymmetry of the frequency response prevents the use of real analysis filters. In the investigation presented in this thesis, complex analysis filters and real'synthesis filters are used in the classical structure, to reduce the aliasing errors and to achieve superior convergence rate. PRFB is traditionally used in implementing Interpolated FIR (IFIR) structure. These filters may not be ideal for processing an input signal for an adaptive algorithm. As third contribution, the IFIR structure is modified using discrete finite frames. The model of an FIR filter s is given by Fc, with c = Hs. The columns of the matrix F forms a frame with rows of H as its dual frame. The matrix elements can be arbitrary except that the transformation should be implementable as a filter bank. This freedom is used to optimize the filter bank, with the knowledge of the input statistics, for initial convergence rate enhancement . Next, the proposed subband adaptive algorithms are applied to acoustic echo cancellation problem with realistic parameters. Speech input and sufficiently long Room Impulse Response (RIR) are used in the simulations. The Echo Return Loss Enhancement (ERLE)and the steady state error spectrum are used as performance measures to compare these algorithms with the full band scheme and other representative subband implementations. Finally, Subband adaptive algorithm is used in minimization of EOG (Electrooculogram) artefacts from measured EEG (Electroencephalogram) signal. An IIR filterbank providing sufficient isolation between the frequency bands is used in the modified IFIR structure and this structure has been employed in the artefact minimization scheme. The estimation error in the high frequency range has been reduced and the output signal to noise ratio has been increased by a couple of dB over that of the fullband scheme. Conclusions Efforts to find elegant Subband adaptive filtering algorithms will continue in the future. However, in this thesis, the generalized filtering algorithm could offer gain in filtering complexity of the order of M/2 and reduced misadjustment . The complex classical scheme offered improved convergence rate, reduced misadjustment and computational gains of the order of M/4 . The modifications of the IFIR structure using discrete finite frames made it possible to eliminate the processing delay and enhance the convergence rate. Typical performance of the complex classical case for speech input in a realistic scenario (8 channel case), offers ERLE of more than 45dB. The subband approach to EOG artefact minimization in EEG signal was found to be superior to their fullband counterpart. (Refer PDF file for Formulas)

Les lésions de la moelle épinière ont un impact significatif sur la qualité de la vie car elles peuvent induire des déficits moteurs (paralysie) et sensoriels. Ces déficits évoluent dans le temps à mesure que le système nerveux central se réorganise, en impliquant des mécanismes physiologiques et neurochimiques encore mal connus. L'ampleur de ces déficits ainsi que le processus de réhabilitation dépendent fortement des voies anatomiques qui ont été altérées dans la moelle épinière. Il est donc crucial de pouvoir attester l'intégrité de la matière blanche après une lésion spinale et évaluer quantitativement l'état fonctionnel des neurones spinaux. Un grand intérêt de l'imagerie par résonance magnétique (IRM) est qu'elle permet d'imager de façon non invasive les propriétés fonctionnelles et anatomiques du système nerveux central. Le premier objectif de ce projet de thèse a été de développer l'IRM de diffusion afin d'évaluer l'intégrité des axones de la matière blanche après une lésion médullaire. Le deuxième objectif a été d'évaluer dans quelle mesure l'IRM fonctionnelle permet de mesurer l'activité des neurones de la moelle épinière. Bien que largement appliquées au cerveau, l'IRM de diffusion et l'IRM fonctionnelle de la moelle épinière sont plus problématiques. Les difficultés associées à l'IRM de la moelle épinière relèvent de sa fine géométrie (environ 1 cm de diamètre chez l'humain), de la présence de mouvements d'origine physiologique (cardiaques et respiratoires) et de la présence d'artefacts de susceptibilité magnétique induits par les inhomogénéités de champ, notamment au niveau des disques intervertébraux et des poumons. L'objectif principal de cette thèse a donc été de développer des méthodes permettant de contourner ces difficultés. Ce développement a notamment reposé sur l'optimisation des paramètres d'acquisition d'images anatomiques, d'images pondérées en diffusion et de données fonctionnelles chez le chat et chez l'humain sur un IRM à 3 Tesla. En outre, diverses stratégies ont été étudiées afin de corriger les distorsions d'images induites par les artefacts de susceptibilité magnétique, et une étude a été menée sur la sensibilité et la spécificité de l'IRM fonctionnelle de la moelle épinière. Les résultats de ces études démontrent la faisabilité d'acquérir des images pondérées en diffusion de haute qualité, et d'évaluer l'intégrité de voies spinales spécifiques après lésion complète et partielle. De plus, l'activité des neurones spinaux a pu être détectée par IRM fonctionnelle chez des chats anesthésiés. Bien qu'encourageants, ces résultats mettent en lumière la nécessité de développer davantage ces nouvelles techniques. L'existence d'un outil de neuroimagerie fiable et robuste, capable de confirmer les paramètres cliniques, permettrait d'améliorer le diagnostic et le pronostic chez les patients atteints de lésions médullaires. Un des enjeux majeurs serait de suivre et de valider l'effet de diverses stratégies thérapeutiques. De telles outils représentent un espoir immense pour nombre de personnes souffrant de traumatismes et de maladies neurodégénératives telles que les lésions de la moelle épinière, les tumeurs spinales, la sclérose en plaques et la sclérose latérale amyotrophique. / Spinal cord injury has a significant impact on quality of life since it can lead to motor (paralysis) and sensory deficits. These deficits evolve in time as reorganisation of the central nervous system occurs, involving physiological and neurochemical mechanisms that are still not fully understood. Given that both the severity of the deficit and the successful rehabilitation process depend on the anatomical pathways that have been altered in the spinal cord, it may be of great interest to assess white matter integrity after a spinal lesion and to evaluate quantitatively the functional state of spinal neurons. The great potential of magnetic resonance imaging (MRI) lies in its ability to investigate both anatomical and functional properties of the central nervous system non invasively. To address the problem of spinal cord injury, this project aimed to evaluate the benefits of diffusion-weighted MRI to assess the integrity of white matter axons that remain after spinal cord injury. The second objective was to evaluate to what extent functional MRI can measure the activity of neurons in the spinal cord. Although widely applied to the brain, diffusion-weighted MRI and functional MRI of the spinal cord are not straightforward. Various issues arise from the small cross-section width of the cord, the presence of cardiac and respiratory motions, and from magnetic field inhomogeneities in the spinal region. The main purpose of the present thesis was therefore to develop methodologies to circumvent these issues. This development notably focused on the optimization of acquisition parameters to image anatomical, diffusion-weighted and functional data in cats and humans at 3T using standard coils and pulse sequences. Moreover, various strategies to correct for susceptibility-induced distortions were investigated and the sensitivity and specificity in spinal cord functional MRI was studied. As a result, acquisition of high spatial and angular diffusion-weighted images and evaluation of the integrity of specific spinal pathways following spinal cord injury was achieved. Moreover, functional activations in the spinal cord of anaesthetized cats was detected. Although encouraging, these results highlight the need for further technical and methodological development in the near-future. Being able to develop a reliable neuroimaging tool for confirming clinical parameters would improve diagnostic and prognosis. It would also enable to monitor the effect of various therapeutic strategies. This would certainly bring hope to a large number of people suffering from trauma and neurodegenerative diseases such as spinal cord injury, tumours, multiple sclerosis and amyotrophic lateral sclerosis.

We live in a high tech era of electronic media, which is changing our lives (Giddens, 1999). Apps are examples of technologies that affect our lives. An interesting question in this context is what apps will have for significance; on one hand for the development of technology, and on other hand for humans’ relation to technology. Since the development and change process are central issues in the science of education I will explore the development of applications. The purpose of this paper is to seek knowledge about applications (apps) development from a design and user perspective. This dissertation discusses activity theory as an academic framework for understanding of apps development from two different types of operating systems or practices, to be precise design practice and user practice. To clarify my point, I have defined the following questions: why user apps are designed, how user apps are designed, and what contradictions occur between the design and the use of apps? My research is based on a qualitative approach with an abductive approach. I used multiple case studies as research approach based on three data collection techniques: interviews, observiews (interviews and observations) and observations of social media and an archived document of wireframes about apps. The result shows that apps designed and published either for their function or for promotional purposes. The design process is fast and dynamic process where applications are published before they are ready and constantly updated later. The use of apps characterized by either an active or a passive use operations. In the passive activity apps are tested through trial and error, and when they do not meet the user's expectations they are thrown away. This activity contributes in relation to previous research on technology and social change to the consumer’s throwaway culture. While in the active using, activities becomes part of the development activities where development aspects are communicated through social media – interact active users and designers to develop the app, which is both an artifact and an object of their own development. Activity theory thus contributes to theories of design by considering design not only as production but also as a fully operational system itself with the production, consumption, exchange and distribution. / Vi lever i en högmodern tid som präglas av elektroniska medier som förändrar vårt liv enligt Giddens (1999). Appar är exempel på teknik som påverkar vårt liv. En intressant fråga i detta sammanhang är vad appar får för betydelse för – å ena sidan utveckling av teknik å andra sidan människans förhållande till teknik. Eftersom utveckling och förändringsprocesser är centrala i pedagogik vill jag studera utveckling av appar. Syftet med denna uppsats är att söka kunskap om apputveckling ur ett design- och användarperspektiv. I uppsatsen används verksamhetsteori som teoretiskt ramverk för att förstå apputveckling utifrån två olika typer av verksamhetssystem eller praktiker, nämligen designpraktiken och användarpraktiken. För att närmare precisera mitt syfte har jag definierat följande frågeställningar: varför designas respektive används appar, hur designas respektive används appar, och vilka motsättningar uppstår/finns mellan design och användning av appar? Min uppsats bygger på ett kvalitativt tillvägagångssätt med en abduktiv ansats som innebär en pendling mellan teori och empiri. Jag använder flerfallsstudien som forskningsansats, med tre datasamlingstekniker: intervjuer, observjuer och observationer av sociala medier och ett arkiverat dokument med skisser över appar. Resultatet visar att appar designas och publiceras antingen för sin funktion eller i marknadsföringssyfte. Designprocessen är en snabb, dynamisk process där appar publiceras innan de är klara och därefter ständigt uppdateras. Användning av appar kännetecknas av antingen en aktiv eller en passiv användning. I den passiva användningsverksamheten prövas appar genom trial-and-error och när de inte motsvarar användarens förväntningar kastas de bort. Denna verksamhet bidrar i relation till tidigare forskning om teknik och social förändring till konsumtionssamhällets slit och slängkultur. Den aktiva användningsverksamheten blir istället en del av utvecklings­verksamheten där utvecklingsaspekter kommuniceras via sociala medier där aktiva användare och designer samverkar i att utveckla appen som blir både en artefakt och ett objekt för sin egen utveckling. Verksamhetsteori bidrar således till teorier om design genom att betrakta design inte bara som produktion utan som ett helt verksamhetssystem i sig med produktion, konsumtion, utbyte och fördelning.