Browsing by Author "Mehmet C. Ozturk, Committee Member"

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The Effectiveness of Global Difference Value Prediction And Memory Bus Priority Schemes for Speculative Prefetch
(2003-07-01) Gunal, Ugur; Thomas M. Conte, Committee Chair; Eric Rotenberg, Committee Member; Mehmet C. Ozturk, Committee Member
Processor clock speeds have drastically increased in the recent years. However, the cycle time improvement in the DRAM semiconductor technology used for memories has been comparatively slow. The expanding processor — memory gap encourages developers to find aggressive techniques to reduce the latency of memory accesses. Value prediction is a powerful approach to break true data dependencies. Prefetching is another technique, which aims to reduce the processor stall time by bringing data into the cache before it is accessed by the processor. Recovery-free value prediction [26] scheme combines these two techniques and uses value prediction only for prefetching so that the need for validation of predictions and a recovery mechanism for mispredictions are eliminated. In this thesis, the effectiveness of using global difference value prediction for recovery-free speculative execution is studied. A bus model is added for modeling the buses in the memory system. Three bus priority schemes, First Come First Served (FCFS), Real Access First Served (RAFS) and Prefetch Access First Served (PAFS), are proposed and their performance potentials are evaluated when a stride and a hybrid global difference predictor (hgDiff) is used. The results show that the recovery-free speculative execution using value prediction is a promising technique that increases the performance significantly (up to 10%), and this increase depends on the bus priority scheme and the predictor used.
Investigation of Europium Doped Wide Band Gap Oxides and an Annealing Study of the Amorphous Oxide Semiconductor - Indium Gallium Zinc Oxide
(2007-01-02) Gollakota, Praveen; Mehmet C. Ozturk, Committee Member; John F. Muth, Committee Co-Chair; Leda M. Lunardi, Committee Chair
The electronic, optical and luminescent properties of europium doped wide band gap oxide thin films and the electronic properties of indium gallium zinc oxide (IGZO), a novel amorphous oxide semiconductor were investigated. The thin films of europium doped gallium and gadolinium oxides and indium gallium zinc oxide were deposited on c-axis oriented sapphire substrates by Pulsed Laser Deposition at various conditions of temperature, pressure and doping concentration. Europium doped gallium oxide was found to be in beta phase with monoclinic crystal structure and the films exhibited intense red emission under cathode ray excitation with a peak wavelength of emission at 611 nm which corresponds to the transitions from ⁵D₀ to ⁷F₂ levels in europium. Europium doped gadolinium oxide thin films were found to exhibit two different phases (cubic and monoclinic) with the one of the phases being dominant depending on the growth conditions. The peak wavelength of emission was either 611 nm or 613 nm depending on the phase of the films. The amorphous indium gallium zinc oxide thin films were found to exhibit very high hall mobilities of the order of ˜15 cm²∙V⁻¹∙s⁻¹ and the conductivity could be controlled over several orders of magnitude from 5 x 10⁻³ S∙cm⁻¹ to 10 S∙cm⁻¹ in the amorphous phase. Annealing the films in presence of air was found to decrease the carrier concentration of the films due the incorporation of oxygen in the films thereby filling up the oxygen vacancies. Applications of amorphous indium gallium zinc oxide include Transparent Thin Film Transistors and use as transparent conducting oxide for optoelectronic devices.
Spectroscopic Investigation of Hf-Si Oxynitride Alloys and Low Temperature Cobalt Metal ALD
(2008-04-21) Oh, Sang Jeong; Gregory N. Parsons, Committee Co-Chair; Mehmet C. Ozturk, Committee Member; Nadia Elmasry, Committee Member; Jon Paul Maria, Committee Co-Chair