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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Infrared-bright galaxies in the millennium simulation and Sunyaev Zeldovich effect contamination

Opolot, Daniel Christopher January 2010 (has links)
>Magister Scientiae - MSc / Measuring the evolution of the abundance of galaxy clusters puts constraints on cosmological parameters like the cosmological density parameter m, σ8 and the dark energy equation of state parameter, w. Current observations that promise to give large cluster counts and their properties are those that rely on the Sunyaev-Zeldovich effect (SZE) from clusters. We study the contamination of the SZ signals from galaxy clusters by cluster infrared (IR) galaxies and particularly faint IR galaxies. We use the Millennium simulation database to extract galaxy clusters and deduce contaminant IR fluxes using the star formation rate - IR luminosity relations. We use the IR spectral energy distribution(SED) to obtain the monochromatic fluxes at 145 GHz, 217 GHz and 265 GHz, which are the observation frequencies of the Atacama Cosmology Telescope (ACT). Taking ACT as a case study, we selected all clusters with Mvir ≥ 2 × 1014 M⊙, and consider all galaxies in a cluster with star formation rate sfr ≥ 0.2 M⊙yr−1 as IR galaxies. From the fluxes of these selected sources, we compute their contribution to the SZE temperature fluctuations.We find that the galaxies in clusters have a non-neglible contribution to the SZ signals.In massive and rich clusters the contribution can be as high as 100 μK at z = 0.36,which is substantial when compared to the thermal SZE of & 270μK for such clusters.This effect can be reduced significantly if proper modelling of IR sources is done to pick out the point sources within clusters. We also find that irrespective of the mass range,the average contaminant temperature fluctuation T can be modelled as a power-law: T = Czm, where z is the redshift, m = 1.8 ± 0.07 and C takes on a range of values(0.008 to 0.9) depending on the cluster mass and the observation frequency respectively.We also study some properties of simulated galaxy clusters like substructures in clusters,2D projected distributions and number density profiles, which are all discussed in the results.
2

Embodied vulnerabilities : responding to violent encounters through installation practices

Haynes, Rachael Anne January 2009 (has links)
This practice-led research was initiated in response to a series of violent encounters that occurred between my fragile installations and viewers. The central focus of this study was to recuperate my installation practice in the wake of such events. This led to the development of a ‘responsive practice’ methodology, which reframed the installation process through an ethical lens developed from Emmanuel Levinas’ ethical phenomenology. The central propositions of this research are the reconceptualisation of ‘violent encounters’ in terms of difference whereby I accept viewers responses, even those which are violent, destructive or damaging, and secondly that the process operates as a generative excess for practice through which recuperative strategies can be found and implemented. By re-examining this process as it unfolded in the three phases of the practical component, I developed strategies whereby violated, destroyed or damaged works could be recuperated through the processes of reconfiguration, reparation and regeneration. Therefore my installations embody and articulate vulnerability but also demonstrate resilience and renewal.
3

Framework pro hardwarovou akceleraci 400Gb sítí / Framework for Hardware Acceleration of 400Gb Networks

Hummel, Václav January 2017 (has links)
The NetCOPE framework has proven itself as a viable framework for rapid development of hardware accelerated wire-speed network applications using Network Functions Virtualization (NFV). To meet the current and future requirements of such applications the NetCOPE platform has to catch up with upcoming 400 Gigabit Ethernet. Otherwise, it may become deprecated in following years. Catching up with 400 Gigabit Ethernet brings many challenges bringing necessity of completely different way of thinking. Multiple network packets have to be processed each clock cycle requiring a new concept of processing. Advanced memory management is used to ensure constant memory complexity with respect to the number of DMA channels without any impact on performance. Thanks to that, even more than 256 completely independent DMA channels are feasible with current technology. A lot of effort was made to create the framework as generic as possible allowing deployment of 400 Gigabit Ethernet and beyond. Emphasis is put on communication between the framework and host computer via PCI Express technology. Multiple Ethernet ports are also considered. The proposed system is prepared to be deployed on the family of COMBO cards, used as a reference platform.

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