Browsing by Subject "SOC"
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Item Biogeochemistry of the Western Gulf Coastal Plain as Impacted by Forest Management(2014-01-29) Foote, JuliePlantation forestry is central to supplying the global demand for forest products and sustainable production will rely on information regarding the effects of disturbance on soil biogeochemistry. The extent of ecosystem disturbance will dictate the degree to which biogeochemical processes are perturbed. To date little is known about the impact of forest harvest activities on biogeochemical cycling in the western Gulf Coastal Plain, therefore the purpose of this study was to elucidate the impact of three harvest methods (bole only, whole tree, whole tree+forest floor removal) in factorial combination with three soil compaction intensities (none, intermediate, severe) 15-years following treatment and in an archived soil time-series in a Pinus taeda L. forest. I evaluated soil microbial biomass (SMB), and soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) storage, and stable isotopes ^(15)N and ^(13)C. I used chloroform fumigation extraction, dry combustion, and lithium metaborate fusion to quantify SMB, SOC and TN, and TP, respectively, and isotope ratio mass spectrometry to analyze 15N and 13C. Soil microbial biomass, TN, and TP decreased significantly in the order: bole only > whole tree > whole tree+forest floor removal; although not significant SOC followed the same pattern. Soil TN, litter and root N were generally ^(15)N enriched under the whole tree+forest floor removal treatment. Compared to control plots, harvest initially resulted in lower TN and SOC that was enriched in ^(15)N and ^(13)C, however, both C and N have been accumulating since 5-years post-treatment and have become increasingly less enriched isotopically. No evidence of a compaction or a harvest by compaction interaction effect was found on the measured variables. Although both C and N are accumulating, there were losses initially following harvest as evidenced by isotopic enrichment. Forest harvest practices that minimize removal of above-ground biomass will likely favor soil N and P retention and maintenance of the SMB pool. Since both N and P limit productivity in the sandy soils of this region, and because SMB plays a key role in nutrient cycling, harvest practices that favor nutrient retention and SMB will ensure the productivity of future rotations.Item Dynamic Power Management of High Performance Network on Chip(2012-02-14) Mandal, Suman KalyanWith increased density of modern System on Chip(SoC) communication between nodes has become a major problem. Network on Chip is a novel on chip communication paradigm to solve this by using highly scalable and efficient packet switched network. The addition of intelligent networking on the chip adds to the chip?s power consumption thus making management of communication power an interesting and challenging research problem. While VLSI techniques have evolved over time to enable power reduction in the circuit level, the highly dynamic nature of modern large SoC demand more than that. This dissertation explores some innovative dynamic solutions to manage the ever increasing communication power in the post sub-micron era. Today?s highly integrated SoCs require great level of cross layer optimizations to provide maximum efficiency. This dissertation aims at the dynamic power management problem from top. Starting with a system level distribution and management down to microarchitecture enhancements were found necessary to deliver maximum power efficiency. A distributed power budget sharing technique is proposed. To efficiently satisfy the established power budget, a novel flow control and throttling technique is proposed. Finally power efficiency of underlying microarchitecture is explored and novel buffer and link management techniques are developed. All of the proposed techniques yield improvement in power-performance efficiency of the NoC infrastructure.Item Integration of virtual platform models into a system-level design framework(2010-05) Salinas Bomfim, Pablo E.; Gerstlauer, Andreas, 1970-; John, Lizy K.The fields of System-On-Chip (SOC) and Embedded Systems Design have received a lot of attention in the last years. As part of an effort to increase productivity and reduce the time-to-market of new products, different approaches for Electronic System-Level Design frameworks have been proposed. These different methods promise a transparent co-design of hardware and software without having to focus on the final hardware/software split. In our work, we focused on enhancing the component database, modeling and synthesis capabilities of the System-On-Chip Environment (SCE). We investigated two different virtual platform emulators (QEMU and OVP) for integration into SCE. Based on a comparative analysis, we opted on integrating the Open Virtual Platforms (OVP) models and tested the enhanced SCE simulation, design and synthesis capabilities with a JPEG encoder application, which uses both custom hardware and software as part of the system. Our approach proves not only to provide fast functional verification support for designers (10+ times faster than cycle accurate models), but also to offer a good speed/accuracy relationship when compared against integration of cycle accurate or behavioral (host-compiled) models.Item Microprocessor power management and a stand-alone benchmarking application for Android based platforms(2011-12) Yeager, Hans L.; Aziz, Adnan; Gerstlauer, AndreasComponents used in mobile hand-held devices (smart phones and tablets) vary greatly in performance and power consumption. The microprocessors used in these devices also have vastly different capabilities and manufacturing limitations leading to significant variation effects. Battery life is a significant concern to the end users of these products. A stand-alone Android application capable of benchmarking a device's performance and power consumption is introduced. The application does not require the end user to have any analytic equipment or to have a technical background. This enables individual end users to better understand their particular device's performance and battery life interaction. They may also use the application to determine if their device's performance or battery life has degraded over time. Data is also uploaded to a central location so that devices can be compared against each other. The benchmarking application is capable of resolving variation effects caused by device, environmental changes and power management actions. This application demonstrates the feasibility of creating a low cost ecosystem where thousands of devices can be quantitatively compared.