Energy-aware embedded media processing: customizable memory subsystems and energy management policies

textThe design of energy-efficient data memory architectures for embedded system platforms has received considerable attention in recent years. In this dissertation we propose a special-purpose data memory subsystem, called Xtream-Fit, targeted to streaming media applications executing on both generic uniprocessor embedded platforms and powerful SMT-based multi-threading platforms. We empirically demonstrate that Xtream-Fit achieves high energydelay efficiency across a wide range of media devices, from systems running a single media application to systems concurrently executing multiple media applications under synchronization constraints. Xtream-Fit’s energy efficiency is predicated on a novel task-based execution model that exposes/enhances opportunities for efficient prefetching, and aggressive dynamic energy conservation techniques targeting on-chip and off-chip memory components. A key novelty of Xtream-Fit is that it exposes a single customization parameter, thus enabling a very simple and yet effective design space exploration methodology to find the best memory configuration for the target application(s). Extensive experimental results show that Xtream-Fit reduces energy-delay product substantially – by 32% to 69% – as compared to ‘standard’ general-purpose memory subsystems enhanced with state of the art cache decay and SDRAM power mode control policies.Electrical and Computer Engineerin

Methodologies for Transient Simulation of Hybrid Electromagnetic/Circuit Systems with Multiple Time Scales

This work presents methodologies to facilitate the efficient cosimulation of electromagnetic/circuit systems while exploiting the multiple time scales that are often present in the numerical simulation of such systems. Three distinct approaches are presented to expedite such a simulation process, with the common theme that the methodologies should allow for the ability to utilize different timesteps in the simulation procedure for the different components appearing in a hybrid system. The first contribution involves a direct representation of each of Maxwell???s curl equations in terms of SPICE-equivalent circuit stamps. This provides for a full-wave, circuit-compatible description of a distributed structure that can very naturally be incorporated into a circuit simulation environment. This capability can be applied to circuit simulations of distributed structures, or it can facilitate the detailed simulation of an electrically small structure with full electromagnetic accuracy. The second contribution allows for the utilization of different numerical integration schemes and timesteps in the simulation of hybrid structures via a domain decomposition approach. By introducing a novel scheme to combine finite-difference time-domain simulation with SPICE-like circuit simulation, it is shown that the timestep used in the lumped circuit portions need not be limited by the Courant-Friedrichs-Lewy (CFL) limit which governs the timestep used in distributed portions. Additionally, the use of the Crank-Nicolson integration scheme is investigated for the simulation of transmission line structures, and an efficient methodology is proposed by combining the Crank-Nicolson integration of transmission lines and standard integration of circuits. Finally, the third contribution in this work involves efficient simulation of circuits involving multirate signals with widely separated time scales. An efficient representation of multirate signals is found by introducing a different time variable for each time scale in order to overcome the significant oversampling of such signals that arises from more traditional, univariate representations. This representation is then directly applied to the simulation of transmission line structures. It is found that the resulting methodologies provide for a significant speedup in the overall simulation time

Performance, Combustion and Emission Characteristics of a D.I. Diesel Engine Fuelled with Nanoparticle Blended Jatropha Biodiesel

The effect of nanoparticle as additive in Jatropha biodiesel is experimentally investigated in a single cylinder DI diesel engine with the aim of diluting the level of pollutants in the exhaust and for the improvement of engine performance owing to its potential advantage of high surface area to volume ratio, acting as a catalyst for the better combustion. Alumina and Cerium oxide nanoparticles are blended separately with Jatropha biodiesel at 30 parts per million and the engine performance, combustion and emission characteristics are compared with neat diesel and neat biodiesel as base fuels. For alumina blended test fuel, percentage reduction of NO emission by 9 %, Smoke opacity by 17 %, unburned hydrocarbon by 33 % and carbon monoxide by 20 % are observed along with percentage reduction of NO emission by 7 %, Smoke opacity by 20 %, unburned hydrocarbon by 28 % and carbon monoxide by 20 % for cerium oxide blended test fuel. 5 % improvement in brake thermal efficiency is observed for both the test fuels, due to its high surface area to volume ratio of nanoparticle promoting better combustion by improved atomization, better mixing of air-mixture and rapid evaporation of the fuel

FPGA acceleration of DNA error correction

Correcting errors in DNA sequencing data is an important process that can improve the quality of downstream analyses using the data. Even though many error-correction methods have been proposed for Illumina reads, their throughput is not high enough to process data from large genomes. The thesis describes the first FPGA-based error-correction tool, which is designed to improve the throughput of DNA error correction for Illumina reads. The base algorithm of the FPGA implementation is BLESS which is highly accurate but slow. The hardware implemented on the FPGA consists of a Bloom filter that is the main data structure of BLESS and the error-correction subroutines in BLESS. The design is compared with the software version of BLESS, and two other leading tools. The results show significant improvements in speed for the FPGA-based implementation with comparable accuracy of error correction

Content Analysis of Indian Versus American Advertising in News Magazines

This study compares advertising in India Today to advertising in Time. All the ads from all six issues of India Today published between March and May 1981 were compared to all the ads from six issues of Time, chosen at random from the same time period. The Statistical Analysis System was used for the analysis. Several major and minor differences were found between Indian and American advertising, which suggest to the international advertiser that it would be unwise to standardize international advertising.Business Administratio

Higher-power harmonic maps and sections

The variational theory of higher-power energy is developed for mappings between Riemannian manifolds, and more generally sections of submersions of Riemannian manifolds, and applied to sections of Riemannian vector bundles and their sphere subbundles. A complete classification is then given for left-invariant vector fields on 3-dimensional unimodular Lie groups equipped with an arbitrary left-invariant Riemannian metric