Parce qu’ils font l’objet d’une utilisation intensive ces dernières années et que leur adoption suit une courbe similaire à celle du taux de pénétration du smartphone, les services de géolocalisation se sont rapidement et solidement ancrés dans le quotidien des individus hyperconnectés. Nous nous interrogeons dans cette recherche doctorale sur les nouvelles expériences au monde qui découlent de l’usage de ces dispositifs à travers une enquête qualitative menée auprès de 62 individus. Nos premiers résultats mettent en évidence que ces services, au même titre que d’autres technologies de l’information et de la communication, contribuent grandement à un réinvestissement des espaces et des lieux, à une relativisation des distances kilométriques et à de nouveaux rapports au temps marqués par une accélération continue et une recherche de l’immédiateté. Mais, les applications géolocalisées se voulant aujourd’hui de plus en plus socialisantes, nous avons également relevé et analysé de nouvelles stratégies de regroupement, d’évitement, de surveillance voire de contrôle entre des individus. Cela amène parfois à de nouveaux rapports de forces entre un géolocalisant et un géolocalisé, intimement liés aux problématiques de la visibilité, de la visualité et de l’anonymat dans un espace urbain hybridé où le partage de la position géographique est devenu quasiment permanent. / Because of their increasing and intensive use over the last few years, roughly similar to the smartphone penetration rate, Location-Based Services (LBS) have quickly and strongly become rooted in the everyday’s life of the hyperconnected user. We are questionning ourselves in this PhD research on the new experiences to the world brought by the use of such devices throughout a qualitative survey conducted among 62 LBS users. Our first results highlight that those LBS, like some other information and communication technologies, largely contribute in the reinvestment of space and places, while they are creating a relativization of metric distance over the temporal one and new ways to experience time defined by a continuous acceleration and a search for immediacy. But, as LBS are becoming more and more socializing, we also noticed and analyzed new grouping and dodging strategies, as well as new ways to watch over and possibly control people. This sometimes leads to new balances of power between the one who is tracking and the one who is being tracked, deeply linked to discussions over visibility, visuality and anonymity in a hybrid urban space where the share of location has become almost continuous.

Virtual crowd rendering have been used in film industry with offine rendering methods for a long time. But its existence in interactive real-time applications such as video games is not so common due to the limited rendering power of current graphics hardware. This thesis describes a novel method to improve shadow mapping performance of a crowded scene by taking into account the screen space visibility of the casted shadow of a crowd instance when rendering the shadow maps. A grid-based visibility mask creation method is proposed which is irrelevant to scene complexity. This improves the rendering performance especially when there are many occluded instances of the crowd which is a common scenario in urban environments and accelerates the usage of crowds in real time applications, such as games. We compute visibility of all agents in a crowd in parallel on the graphics processing unit(GPU) without having a requirement of a stencil buer or light direction dependent shadow mask. Technique also improves the view space rendering time by reducing the visibility check cost of the agents that are located on the invisible areas of the scene. The methodology introduced in this thesis gets more effective in each shadow map rendering pass by re-using the same visibility mask for shadow caster culling and enables many local lights with shadows. We also give a brief information about the state of the art of crowd rendering and shadowing, explaining how suitable the method with the implementations of different shadow mapping approaches. The technique is very well compatible with the modern crowd rendering techniques such as skinned instancing, dynamic level of detail(LOD) determination and GPU-based simulation.

Durante la última década, el dominio digital se convirtió en una parte integral de nuestra vida cotidiana. Hoy en día, la transición que experimentábamos anteriormente mudando de los espacios actuales de comunicación al ciberespacio, cuando Internet era una novedad en nuestras vidas, ya no es aplicable, pasamos de uno al otro con la facilidad de pasar de una habitación a otra. En este contexto, conocimos la arquitectura participativa de la Web 2.0 y el concepto de las redes sociales online, y poco a poco, hemos pasado de la invisibilidad del ciberespacio a la super-visibilidad que tenemos hoy en día. Con todos estos factores en juego, nuestras formas de definir, entender y construir nuestras identidades han cambiado considerablemente.

In this dissertation, I examine how making infrastructure visible affects users' engagement with that infrastructure, through the case study of home networking. I present empirical evidence of the visibility issues that home networks present to users and how these results informed the design of a prototype called Kermit to visualize aspects of the home network. Through my implementation and evaluation of Kermit, I derive implications for making infrastructure visible in ways that enable end-users to manage and understand the systems they use everyday. I conclude with suggestions for future work for making home networks, and infrastructure more generally, more visible.

It has been noted by several authors that General Relativistic frame dragging in rotating neutron stars is a first order effect which has to be included in a self-consistent model of pulsar magnetospheric structure and associated radiation and transport processes. To this end, I undertook the present study with the aim of investigating the effect of General Relativity (GR) on millisecond pulsar (MSP) visibility. I developed a numerical code for simulating a pulsar magnetosphere, incorporating the GR-corrected expressions for the electric potential and field. I included curvature radiation (CR) due to primary electrons accelerated above the stellar surface, as well as inverse Compton scattering (ICS) of thermal X-ray photons by these electrons. I then applied the model to PSR J0437-4715, a prime candidate for testing the GR-Electrodynamic theory, and examined its visibility for the H.E.S.S. telescope. I also considered the question of whether magnetic photon absorption would take place for this particular pulsar. In addition, I developed a classical model for comparison with the GR results. I found that the typical electron energies and associated CR photon energies are functions of position above the polar cap (PC). These energies are also quite smaller in the GR case than in the classical case due to the different functional forms of the GR and classical electric fields. I found the CR energy cut-off to be ~ 4 GeV compared to the well-known classical value of ~ 100 GeV. Since the H.E.S.S. energy threshold is ~ 100 GeV, it seems as though the CR component will not be visible, contrary to wide-held opinion. However, the ICS component seems to be well in excess of the H.E.S.S. energy threshold and is expected to be visible. I also found that no pair production will take place for PSR J0437-4715. Hopefully, forthcoming H.E.S.S. observations will provide validation of these results. KEY WORDS: General relativistic frame dragging, GR electrodynamics, millisecond pulsar visibility, non-thermal radiation processes, pair production, H.E.S.S., individual pulsars: PSR J0437-4715. / Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2004.

The first decade of this century marked a moment of hypervisibility for lesbians and bisexual women on British television. During this time, however, lesbian hypervisibility was coded repeatedly as hyperfemininity. When the BBC and ITV adapted Sarah Waters’s novels for television, how, I ask, did the screen versions balance the demands of pop visual culture with the novels’ complex, unconventional – and in some cases subversive – representations of lesbianism? I pursue this question with an interdisciplinary methodology drawn from queer and feminist theories, cultural and media studies, and film adaptation theory. Chapter Two looks back to Jeanette Winterson’s Oranges Are Not the Only Fruit (BBC 1990). I examine this text – the first BBC television serial to feature a lesbian protagonist – to establish a vocabulary for discussing the page-to-screen adaptation of queer identities throughout this dissertation. Chapter Three investigates Waters’s first novel Tipping the Velvet (1998) and its complex intertextual relationship with Andrew Davies’s serialized version (BBC 2002). I also examine responses to the serial in the British press, tracing the ways in which dominant cultural forces seek to domesticate non-normative instances of gender and sexuality. Chapter Four examines Waters’s novel Fingersmith (2002) in relation to Peter Ransley’s adaptation (BBC 2005) to situate adaptations of Waters’s retro-Victorian texts amid the genre of television and film adaptations of Jane Austen novels. I argue that Ransley’s serial interrogates the notion of Austen as a “conservative icon” (Cartmell 24) and queers the Austen adaptation genre itself. To conclude this study I address Davies’s television film (ITV 2008) of Waters’s second novel Affinity (1999). In this chapter I examine how the adaptation depicts the disruptive lesbian at the centre of the text. I argue in particular that by casting an actress who does not conform to dominant televisual norms of femininity, the adaptation is able to create a powerful audiovisual transgendered moment which adds to the novel’s destabilization of Victorian hierarchies of gender and class. This chapter considers, finally, how Tipping the Velvet, Fingersmith and Affinity have contributed to lesbian visibility on British television. / Thesis (Ph.D, English) -- Queen's University, 2009-05-27 11:26:42.504

People describe and explore space with a strong emphasis on the visual senses, yet modelling the field of view has received little attention within the realm of Location Based Services (LBS), in part due to the lack of useful data. Advances in data capture, such as Light Detection and Ranging (LiDAR), provide new opportunities to build digital city models and expand the range of applications which use visibility analysis. This thesis capitalises on these advances with the development of a visibility model to support a number of innovative LBS functions in an urban region and particular focus is given to the visibility model‟s supporting role in the formation of referring expressions, the descriptive phrases used to identify objects in a scene, which are relevant when delivering spatial information to the user through a speech based interface. Speech interfaces are particularly useful to mobile users with restricted screen viewing opportunities, such as navigational support for motorists and a wider range of tasks including delivering information to urban pedestrians. As speech recognition accuracies improve so new interaction opportunities will allow users to relate to their surroundings and retrieve information on buildings in view through spoken descriptions. The papers presented in this thesis work towards this goal, by translating spatial information into a form which matches the user‟s perspective and can be delivered over a speech interface. The foundation is the development of a new visual exposure model for use in urban areas, able to calculate a number of metrics about Features of Interest (FOIs), including the façade area visible and the percentage on the skyline. The impact of urban vegetation as a semi-permeable visual barrier is also considered, and how visual exposure calculations may be adjusted to accommodate under canopy and through canopy views. The model may be used by pedestrian LBSs, or applied to vehicle navigation tasks to determine how much of a route ahead is in view for a car driver, identifying the sections with limited visibility or the best places for an overtaking manoeuvre. Delivering information via a speech interface requires FOI positions to be defined according to projective space relating to the user‟s viewpoint, rather than topological or metric space, and this is handled using a new egocentric model. Finally descriptions of the FOIs are considered, including a method to automatically collect façade colours by excluding foreground objects, and a model to determine the most appropriate description to direct the LBS user‟s attention to a FOI in view.

It has been noted by several authors that General Relativistic frame dragging in rotating neutron stars is a first order effect which has to be included in a self-consistent model of pulsar magnetospheric structure and associated radiation and transport processes. To this end, I undertook the present study with the aim of investigating the effect of General Relativity (GR) on millisecond pulsar (MSP) visibility. I developed a numerical code for simulating a pulsar magnetosphere, incorporating the GR-corrected expressions for the electric potential and field. I included curvature radiation (CR) due to primary electrons accelerated above the stellar surface, as well as inverse Compton scattering (ICS) of thermal X-ray photons by these electrons. I then applied the model to PSR J0437-4715, a prime candidate for testing the GR-Electrodynamic theory, and examined its visibility for the H.E.S.S. telescope. I also considered the question of whether magnetic photon absorption would take place for this particular pulsar. In addition, I developed a classical model for comparison with the GR results. I found that the typical electron energies and associated CR photon energies are functions of position above the polar cap (PC). These energies are also quite smaller in the GR case than in the classical case due to the different functional forms of the GR and classical electric fields. I found the CR energy cut-off to be ~ 4 GeV compared to the well-known classical value of ~ 100 GeV. Since the H.E.S.S. energy threshold is ~ 100 GeV, it seems as though the CR component will not be visible, contrary to wide-held opinion. However, the ICS component seems to be well in excess of the H.E.S.S. energy threshold and is expected to be visible. I also found that no pair production will take place for PSR J0437-4715. Hopefully, forthcoming H.E.S.S. observations will provide validation of these results. KEY WORDS: General relativistic frame dragging, GR electrodynamics, millisecond pulsar visibility, non-thermal radiation processes, pair production, H.E.S.S., individual pulsars: PSR J0437-4715. / Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2004.

Language landscape or linguistic landscape studies are a relatively new field of research within language sociology that has a specific interest in the public space (Shohamy, 2006:128). Linguistic landscape studies analyzes the use of language in the public and/or institutional sphere~ to determine the (instrumental or symbolical) value represented by the graphic representation of language, taking into account the relevant language policy (see also Gorter, 2007:5; Curtin, 2007:11). The goal of this research is to test and empirically apply the theory of the developing international and national linguistic landscape research paradigm on the multilingual South African higher education landscape. The design for this research consists of a theoretical and an empirical component. The aforementioned entails a thorough investigation of linguistic landscape studies and its development over the past couple of years. The empirical component is done in three phases. Phase 1 involves an in-depth investigation regarding nine of the 12 South African universities whose language policies are available in the public domain. During Phase 2, these universities are visited and structured interviews are held with the language committee/language manager to determine what the situation is regarding policy and practice in the language landscape domain. In Phase 3, the data from the previous two phases is assessed and interpreted to make recommendations to South African universities as to how to overcome the possible mismatch. This research found that the visibility of multilingualism in the South African higher education landscape is relatively low due to a mismatch between policy and practice. However, the mismatch is not caused by universities' lack of commitment to multilingualism. Deep-set causes, i.e. the processes involved with language planning, the lack of detailed language plans, and so forth, lead to this mismatch and the lack of visibility of multilingualism at South African universities. / Thesis (M.A. (Afrikaans and Dutch))--North-West University, Potchefstroom Campus, 2009.

Language landscape or linguistic landscape studies are a relatively new field of research within language sociology that has a specific interest in the public space (Shohamy, 2006:128). Linguistic landscape studies analyzes the use of language in the public and/or institutional sphere~ to determine the (instrumental or symbolical) value represented by the graphic representation of language, taking into account the relevant language policy (see also Gorter, 2007:5; Curtin, 2007:11). The goal of this research is to test and empirically apply the theory of the developing international and national linguistic landscape research paradigm on the multilingual South African higher education landscape. The design for this research consists of a theoretical and an empirical component. The aforementioned entails a thorough investigation of linguistic landscape studies and its development over the past couple of years. The empirical component is done in three phases. Phase 1 involves an in-depth investigation regarding nine of the 12 South African universities whose language policies are available in the public domain. During Phase 2, these universities are visited and structured interviews are held with the language committee/language manager to determine what the situation is regarding policy and practice in the language landscape domain. In Phase 3, the data from the previous two phases is assessed and interpreted to make recommendations to South African universities as to how to overcome the possible mismatch. This research found that the visibility of multilingualism in the South African higher education landscape is relatively low due to a mismatch between policy and practice. However, the mismatch is not caused by universities' lack of commitment to multilingualism. Deep-set causes, i.e. the processes involved with language planning, the lack of detailed language plans, and so forth, lead to this mismatch and the lack of visibility of multilingualism at South African universities. / Thesis (M.A. (Afrikaans and Dutch))--North-West University, Potchefstroom Campus, 2009.