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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.
761

Non-invasive IC tomography using spatial correlations

January 2010 (has links)
We introduce a new methodology for post-silicon characterization of the gate-level variations in a manufactured Integrated Circuit (IC). The estimated characteristics are based on the power and the delay measurements that are affected by the process variations. The power (delay) variations are spatially correlated. Thus, there exists a basis in which variations are sparse. The sparse representation suggests using the L1-regularization (the compressive sensing theory). We show how to use the compressive sensing theory to improve post-silicon characterization. We also address the problem by adding spatial constraints directly to the traditional L2-minimization. The proposed methodology is fast, inexpensive, non-invasive, and applicable to legacy designs. Noninvasive IC characterization has a range of emerging applications, including post-silicon optimization, IC identification, and variations' modeling/simulations. The evaluation results on standard benchmark circuits show that, in average, the gate level characteristics estimation accuracy can be improved by more than two times using the proposed methods.
762

BeamSwitch: System solution for energy-efficient directional communication on mobile devices

January 2010 (has links)
Directional communication has the potential to improve both the energy efficiency of wireless communication without sacrificing its quality. We present a system solution, BeamSwitch, for directional communication on mobile devices. BeamSwitch employs a special multi-antenna system that consists of multiple identical directional antenna or beams, a single regular omni antenna, and a single RF chain. It uses one of the directional beams for transmitting data frames and receiving their acknowledgments and the regular antenna for all other transceiving. BeamSwitch tracks the signal strength of incoming frames and selects the right beam for data transmission. We report an extensive evaluation of BeamSwitch including both measurements with a prototype with three beams and Qualnet-based simulation. Our evaluation shows that BeamSwitch with three 6 dBi directional antennas can improve the energy efficiency of a commercial 802.11 adapter by over 20% and simultaneously provide better or close communication quality. BeamSwitch achieves this under diverse radio propagation environments and extreme mobility (up to 360° per second direction change).
763

Investigations in improving image visualization and quality in positron emission tomography/computed tomography (PET/CT) imaging

January 2010 (has links)
Positron Emission Tomography/Computed Tomography (PET/CT) is a widely used imaging modality for managing patients with cancer. The combination of PET and CT can provide both functional and anatomic information of disease distribution. However, despite its widespread use, it also has some limitations. One drawback is that current PET/CT scanners cannot acquire whole-body scan in a single acquisition but rather has to divide it into multiple sections due to a limitation in the extent of bed travel. The first part of this thesis focuses on developing a software tool that can display multiple PET segments as a single scan to improve the interpretation of these studies. The second part of the thesis focuses on another limitation of PET/CT imaging, namely its low image quality. In this section, an investigation of the correlation between injected dose, patient BMI and scanner design on PET image quality is performed. The objective of this investigation is to determine the significance and extent by which these factors can impact PET image quality. The results of this work can be used as a guide to improve protocol design in an effort to generate an optimal PET image quality.
764

A protocol class for stealing residual bandwidth in uncoordinated distributed wireless networks

January 2010 (has links)
The need for finding effective means of recycling spectrum is becoming increasingly apparent as the world becomes more crowded with wireless devices. While finding a policy solution to this problem will require years, "cognitive radio" is an immediately applicable technology-based solution. Our attention is focused on how a distributed uncoordinated cognitive group of "secondary" users (those with lower priority access to the spectrum) can push data through its network on a single band and in the presence of non-cognitive "primary" users (those with priority access to the spectrum). The main contribution is a novel class of cognitive radio protocols that accomplish this through feedback, where secondaries estimate residual bandwidth and adapt a performance-based parameter. This class of solutions is presented, its parameters are explored and a specific implementation is demonstrated with insights gained.
765

A hybrid relaying protocol for the parallel-relay network

January 2010 (has links)
Cooperation among radios in wireless networks has been shown to improve communication in several aspects. We analyze a wireless network which employs multiple parallel relay transceivers to assist in communication between a single source-destination pair, demonstrating that gains are achieved when a random subset of relays is selected. We derive threshold values for the received signal-to-noise ratios (SNRs) at the relays based on outage probabilities; these thresholds essentially determine the active subset of relays in each time frame for our parallel relay network; due the random nature of wireless channels, this active subset is a random. Two established forwarding protocols for the relays, Amplify-and-Forward and Decode-and-Forward, are combined to create a hybrid relaying protocol which is analyzed in conjunction with both regenerative coding and distributed space-time coding at the relays. Finally, the allocation of power resources to minimize the end-to-end probability of outage is considered.
766

Internetbaserade insamling och behandling av data

Moradi, Hamid January 2008 (has links)
Abstract Aim of this project was to analyse signals and try to localize the position of source of sound. It is done with three microphones which have 90 degrees angle to each other. Each microphone detects one part of the sound wave. The microphones are connected toan ADC which turns signals from analogue to digital shape. After that the three signals are transformed to a computer. As known a computer receives only digital signals which are the main reason to use the ADC. The signals are analysed by computer with help of special softwares. These softwares are LabVIEW and MATLAB which are used in this work. This analysis of the signals is divided in two parts. The first part is the FFT-analyse (Fast Fourier Transform) of the signal from the microphones. It means that the signals frequency’s domain is showed, in other word it shows which frequency components a signal has. Then the result is showed online by a function belonging to LabVIEW which is called Web Publish. In second part the position of the signal source is determined by cross correlation. The position is determined by the difference of time between two signals from same source which are measured by cross correlation and you can determine angle by triangulating which is described in report.
767

Myoelectric Interface

Kus, Emre January 2009 (has links)
The intention of this thesis project report is to control a servo motor by using Electromyography(EMG) signals in the purpose of learning about bioamplifers and how ATMEL AVR Series microcontrollers work. EMG is the a test that is used to record the electrical activity of muscles. In order to fulfill our intention an EMG amplifier, an ADC converter and a servo motor controller is build to be used with the simple mechenical gripper where the control of the gripper is directly related with the amplitude of the EMG signals taken from the hand muscles. In the development and USART serial communication part is also added enabling to see the ADC results in computer.
768

Study, Design and Implementation of an Application Specific Instruction Set Processor for a Specific DSP Task / Study, Design and Implementation of an Application Specific Instruction SetProcessor for a Specific DSP Task

Packiaraj, Vivek January 2008 (has links)
There is a lot of literature already available describing well-structured approach for embeddeddesign and implementation of Application Specific Integrated Processor (ASIP) micro processorcore. This concept features hardware structured approach for implementation of processor core fromminimal instruction set, encoding standards, hardware mapping, and micro architecture design,coding conventions, RTL,verification and burning into a FPGA. The goal is to design an ASIPprocessor core (Micro architecture design and RTL) which can perform DSP task, e.g., FIR. Thereport is a well structured approach of design and implementation of an ASIP DSP processor forDSP applications like FIR. This report contains design flow starting from Instruction set design,micro architecture design and RTL implementation of the core. Details of the power simulationsof FPGA are also listed and analyzed.
769

Standard Interface Between NC-Machine and Industrial Robot / Universell kopplingsbox mellan NC-maskin och industrirobot

Martín, Jose Antonio, Trujillo, Eduardo January 2010 (has links)
The aim of this thesis is the design and implementation of a standardized interface to communicate a NC machine with an industrial robot. This interface consists of an ‘electronic box’ which includes a powerful board that is perfect for automation projects composed of a microcontroller, serial ports, optocouplers, relays, etc… The main component of this PCB is the microcontroller. The Atmel AT90CAN128 microcontroller is a good choice for this purpose since it is perfectly suited for industrial and automotive applications and it supports CANopen and DeviceNet implementation.   The industrial robot’s communication between the board is performed through CAN bus. In order to communicate the interface with the NC machine it has eight optocouplers that are used as inputs and eight relays are used as outputs. Developments of programs using C language to communicate robots and NC machines have been developed by the software that provides Atmel for 8-bit AVR applications called AVR Studio 4 + WinAVR.
770

Algorithm study and Matlab model for  CCITT Group4 TIFF Image Compression

Khan, Azam January 2011 (has links)
Smart cameras are part of many automated system for detection and correction in various systems. They can be used for detecting unwanted particles inside a fuel tank or may be placed on an airplane engine to provide protection from any approaching obstacle. They can also be used to detect a finger print or other biometric identification on a document or in some video domain. These systems usually have a very sensitive fast processing nature, to stop some ongoing information or extract some information. Image compression algorithms are used  for  the  captured  images to enable fast communication between different nodes i.e. the cameras and the processing units. Nowadays these algorithms are very popular with sensor based smart camera. The challenges associated with these networks are fast communication of these images between different nodes or to a centralized system. Thus a study is provided for an algorithm used for this purpose. In-depth study and Matlab modeling of CCITT group4 TIFF is the target of this thesis. This work provides detail study about the CCITT TIFF algorithms and provides a Matlab model for the compression algorithm for monochrome images. The compressed images will be of a compression ratio about 1:15 which will help in fast communication and computation of these images.  A developed set of 8 test images with different characteristics in size and dimension is compressed by the Matlab model implementing the CCITT group4 TIFF. These compressed images are then compared to same set of images compressed by other algorithms to compare the compression ratio.

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