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2007

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Articles 841 - 870 of 910

Full-Text Articles in Electrical and Computer Engineering

Predictive Data Compression Using Adaptive Arithmetic Coding, Claudio Jose Iombo Jan 2007

Predictive Data Compression Using Adaptive Arithmetic Coding, Claudio Jose Iombo

LSU Master's Theses

The commonly used data compression techniques do not necessarily provide maximal compression and neither do they define the most efficient framework for transmission of data. In this thesis we investigate variants of the standard compression algorithms that use the strategy of partitioning of the data to be compressed. Doing so not only increases the compression ratio in many instances, it also reduces the maximum data block size for transmission. The partitioning of the data is made using a Markov model to predict if doing so would result in increased compression ratio. Experiments have been performed on text files comparing the …

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Sigma-Delta Modulation Based Distributed Detection In Wireless Sensor Networks, Dimeng Wang Jan 2007

Sigma-Delta Modulation Based Distributed Detection In Wireless Sensor Networks, Dimeng Wang

LSU Master's Theses

We present a new scheme of distributed detection in sensor networks using Sigma-Delta modulation. In the existing works local sensor nodes either quantize the observation or directly scale the analog observation and then transmit the processed information independently over wireless channels to a fusion center. In this thesis we exploit the advantages of integrating modulation as a local processor into sensor design and propose a novel mixing topology of parallel and serial configurations for distributed detection system, enabling each sensor to transmit binary information to the fusion center, while preserving the analog information through collaborative processing. We develop suboptimal fusion …

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Performance Analysis Of Intel Core 2 Duo Processor, Tribuvan Kumar Prakash Jan 2007

Performance Analysis Of Intel Core 2 Duo Processor, Tribuvan Kumar Prakash

LSU Master's Theses

With the emergence of thread level parallelism as a more efficient method of improving processor performance, Chip Multiprocessor (CMP) technology is being more widely used in developing processor architectures. Also, the widening gap between CPU and memory speed has evoked the interest of researchers to understand performance of memory hierarchical architectures. As part of this research, performance characteristic studies were carried out on the Intel Core 2 Duo, a dual core power efficient processor, using a variety of new generation benchmarks. This study provides a detailed analysis of the memory hierarchy performance and the performance scalability between single and dual …

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Differential Space Time Modulation And Demodulation For Time Varying Multiple Input Multiple Output Channels, Chetan Neginhal Chitnis Jan 2007

Differential Space Time Modulation And Demodulation For Time Varying Multiple Input Multiple Output Channels, Chetan Neginhal Chitnis

LSU Master's Theses

Over the last decade there has been considerable interest in wireless communication using multiple transmit and receive antennas. Several literatures exists that show that these multiple link support very high data rates with low error probabilities when the channel state information is available at the receiver. However when multiple antennas are employed or when the mobile environments change rapidly, it is not always possible to have apriori knowledge of the channel state matrices which calls for Differential Space-Time modulation techniques. Differential modulation is used in conjunction with Unitary Space-Time codes to evaluate their performance over time varying channels. Jakes model …

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A Collaborative High Performance And Grid Computing Portal, Prathyusha Akunuri-Venkata Jan 2007

A Collaborative High Performance And Grid Computing Portal, Prathyusha Akunuri-Venkata

LSU Master's Theses

The world of high performance and grid computing is so vast that it always poses constant challenges and high learning curves to researchers and scientists. A Portal-based solution facilitates a simple web-based graphical user interface that helps the non computer science users take advantage of highly evolving, on-demand, distributed computing to carry out their research activities. A collaborative portal brings together various resources, applications and services under one roof and provides a single point of entry and access to the users. This thesis work endeavors to build a unique High Performance and Grid Computing Portal that combines two existing high …

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A Study On Buckled-Beam Actuators For Rf Mems Applications, Seunghoon Park Jan 2007

A Study On Buckled-Beam Actuators For Rf Mems Applications, Seunghoon Park

LSU Master's Theses

When combined with MEMS actuators, a mechanical lock is a useful device for various applications including memory cells, micro-relays, micro-valves, optical switches, and digital micro-mirrors. It allows removal of actuation force during idle periods without affecting an actuated state of a device, which makes standing power consumption completely unnecessary. In this thesis, a bistable buckled-beam actuator for RF MEMS switch applications has been examined. The buckled-beam geometry was designed based upon theoretical analysis. It was fabricated by SU-8 lithography and copper pulse electroplating. It was actuated by the Lorentz force using external magnet and current flow through the beam. Measured …

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Spike-Based Feature Extraction For Noise Robust Speech Recognition Using Phase Synchrony Coding, Ismail Uysal, Harsha Sathyendra, John G. Harris Jan 2007

Spike-Based Feature Extraction For Noise Robust Speech Recognition Using Phase Synchrony Coding, Ismail Uysal, Harsha Sathyendra, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

We propose a noise robust feature extraction technique for speech signals using phase synchrony. The front-end employs a psychoacoustic cochlea model with inner hair cells to transform speech into a parallel stream of spike trains as observed in the auditory nerve fibers. The degree of phase synchrony among nerve fibers with similar characteristic frequencies is calculated to yield a feature vector which shows little degradation in response to increasing levels of noise. As a benchmark, the feature set is used in a biologically plausible model with a spike-based, liquid state machine classifier for a simple acoustic classification task. Though applied …

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Florida Wireless Implantable Recording Electrodes (Fwire) For Brain Machine Interfaces, Rizwan Bashirullah, John G. Harris, Justin C. Sanchez, Toshikazu Nishida, Jose C. Principe Jan 2007

Florida Wireless Implantable Recording Electrodes (Fwire) For Brain Machine Interfaces, Rizwan Bashirullah, John G. Harris, Justin C. Sanchez, Toshikazu Nishida, Jose C. Principe

Electrical and Computer Engineering Faculty Research & Creative Works

This paper reviews on-going efforts towards the development of the Florida Wireless Implantable Recording Electrodes (FWIRE). The FWIRE microsystem platform is a fully implantable flexible substrate microelectrode array that employs state-of-the-art integrate-and-fire (IF) signal representation and wireless interface circuitry for recording neural activity from behaving rodents. The modular nature of the implantable neural recording electrode allows future enhancements to be seamlessly added to improve functionality including but not limited to rechargeability through inductive coupling, custom microelectrode arrays, higher capacity batteries, and more advanced integrated circuit technologies. This paper concentrates on custom integrated circuits such as neural interfacing amplifiers, baseband signal …

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A Precompensation Algorithm For Pwm-Based Digital Audio Amplifiers For Portable Applications, Xiaoxiang Gong, John G. Harris Jan 2007

A Precompensation Algorithm For Pwm-Based Digital Audio Amplifiers For Portable Applications, Xiaoxiang Gong, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

A novel precompensation algorithm for a Pulse Width Modulation (PWM)-based digital audio amplifier has been developed for portable applications. The Straight-Line Segment PWM (SLSPWM) algorithm results in both low-power and low-complexity devices. The division-free version of this algorithm modifies the algorithm by removing the division using a polynomial approximation. Both SLSPWM and Division-Free SLSPWM feature 16-bit quality performance with fewer calculations compared with previous works. © 2007 IEEE.

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Noise-Robust Automatic Speech Recognition Using A Predictive Echo State Network, Mark D. Skowronski, John G. Harris Jan 2007

Noise-Robust Automatic Speech Recognition Using A Predictive Echo State Network, Mark D. Skowronski, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

Artificial neural networks have been shown to perform well in automatic speech recognition (ASR) tasks, although their complexity and excessive computational costs have limited their use. Recently, a recurrent neural network with simplified training, the echo state network (ESN), was introduced by Jaeger and shown to outperform conventional methods in time series prediction experiments. We created the predictive ESN classifier by combining the ESN with a state machine framework. In small-vocabulary ASR experiments, we compared the noise-robust performance of the predictive ESN classifier with a hidden Markov model (HMM) as a function of model size and signal-to-noise ratio (SNR). The …

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A Pitch Estimation Algorithm Based On The Smooth Harmonic Average Peak-To-Valley Envelope, Arturo Camacho, John G. Harris Jan 2007

A Pitch Estimation Algorithm Based On The Smooth Harmonic Average Peak-To-Valley Envelope, Arturo Camacho, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

We propose SHAPE, a novel pitch estimation algorithm (PEA) that builds upon previous PEAs, addressing and solving some of their limitations. The SHAPE algorithm estimates the pitch using a smooth function to compute the average peak to valley distance at harmonic locations. This is done by performing an integral transform over the square-root magnitude of the spectrum using a truncated decaying cosine as a kernel. SHAPE was designed to both match human perception particularly for inharmonic sounds and to be competitive with numerous other PEAs as demonstrated on a common database. © 2007 IEEE.

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Quasi Group Based Crypto-System, Maruti Venkat Kartik Satti Jan 2007

Quasi Group Based Crypto-System, Maruti Venkat Kartik Satti

LSU Master's Theses

For electronic commerce and other applications it is required to encrypt data that is transmitted over an unsecured channel. The data is encrypted/randomized using a key. Algorithms such as DES and ECC randomize the data such that un-authorized user cannot decrypt it .This thesis presents a practical implementation of a quasi group based multilevel, indexed scrambling transformation for use in signal encryption. Results of experiments with text and speech scrambling are presented. It is shown that the quasi group transformation maximizes the entropy at the output, which is desirable for a good system. This system provides extremely large group of …

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Characterization And Analysis Of Hybrid Electronic Materials For Molecular Based Devices, Sathish Thiruvengadam Jan 2007

Characterization And Analysis Of Hybrid Electronic Materials For Molecular Based Devices, Sathish Thiruvengadam

LSU Master's Theses

The goal of this work is to characterize and to analyze hybrid electronic materials (HEMs) using fluorescence (FL) spectroscopy and conductive probe-atomic force microscopy (CP-AFM) in order to investigate the electrical and optical properties of these materials. Currently, research efforts to characterize novel organic materials for the determination of molecular level transport properties are of great interest.[6] One of the most interesting organic materials is the porphyrin molecule, which exhibits behavior useful for memory applications.[4] Colloidal CdS quantum dots (Q-CdS) capped with dioctyl sulfosuccinate (AOT) and thiol functionalized porphyrin molecules are explored for their potential application to next-generation hybrid electronic …

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Oblivious Transfer For Secure Communication, Abhishek Parakh Jan 2007

Oblivious Transfer For Secure Communication, Abhishek Parakh

LSU Master's Theses

Over the past four decades, computational power and algorithmic strategies have advanced tremendously resulting in an enormous increase in the key sizes required for secure cryptosystems such as RSA. At the same time, the electronic devices have grown smaller and portable requiring algorithms running on them to be optimized in size and efficiency while providing security, at least, equivalent to that provided on a typical desktop computer. As a result, the industry is moving towards newer cryptosystems such as ECC and NTRU that are well suited for resource constrained environments. While, ECC claims to provide security equivalent to that of …

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Fabrication Of Single Walled Carbon Nanotube (Sw-Cnt) Cantilevers For Chemical Sensing, Jui-Ching Hsu Jan 2007

Fabrication Of Single Walled Carbon Nanotube (Sw-Cnt) Cantilevers For Chemical Sensing, Jui-Ching Hsu

LSU Master's Theses

With the discovery of carbon nanotubes (CNTs), many applications have been implemented based on their unique electronic, mechanical, chemical and optoelectronic properties. One area of applications is in gas sensors for detecting, oxygen, flammable and toxic gases. In our work, the focus is on the fabrication of carbon nanotube (CNT) cantilever sensors for integration with CMOS readout chip which offer increased sensitivity. The higher surface-to-bulk ratio enhances the property and performance of the gas sensor by nanocantilevers. In this work, we present the detection method based on the change in capacitance of the single walled carbon nanotube (SWCNT) cantilever. Carbon …

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On-Chip Signal Generation And Response Waveform Extraction For Analog Built-In-Self-Test, Brian Poling Jan 2007

On-Chip Signal Generation And Response Waveform Extraction For Analog Built-In-Self-Test, Brian Poling

Browse all Theses and Dissertations

Built-In Self-Test (BIST) is a method of designing and creating an electronic chip or an electronic system that can self test for correct functionality and ensure no manufacturing defects. The reason for analog BIST is the testing of analog parts of analog and mixed-signal ICs is a costly process that traditionally requires the use of expensive high-end automatic test equipment. Due to the nature of the testing and length of the testing process, an efficient analog BIST scheme is in high demand for the ever increasing complexity of analog and mixed-signal circuits. This thesis presents a BIST scheme for generation …

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Ballistic Graphene Nanoribbon Metal-Oxide-Semiconductor Field-Effect Transistors: A Full Real-Space Quantum Transport Simulation, Gengchiau Liang, Neophytos Neophytou, Mark S. Lundstrom, Dmitri Nikonov Jan 2007

Ballistic Graphene Nanoribbon Metal-Oxide-Semiconductor Field-Effect Transistors: A Full Real-Space Quantum Transport Simulation, Gengchiau Liang, Neophytos Neophytou, Mark S. Lundstrom, Dmitri Nikonov

Department of Electrical and Computer Engineering Faculty Publications

A real-space quantum transport simulator for graphenenanoribbon (GNR) metal-oxide-semiconductor field-effect transistors (MOSFETs) has been developed and used to examine the ballistic performance of GNR MOSFETs. This study focuses on the impact of quantum effects on these devices and on the effect of different type of contacts. We found that two-dimensional (2D) semi-infinite graphene contacts produce metal-induced-gap states (MIGS) in the GNR channel. These states enhance quantum tunneling, particularly in short channel devices, they cause Fermi level pinning and degrade the device performance in both the ON-state and OFF-state. Devices with infinitely long contacts having the same width as the channel …

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A Combinatorial Creativity Approach To Composing Traditional Irish Reels, Nan Zheng, Bryan Duggan Jan 2007

A Combinatorial Creativity Approach To Composing Traditional Irish Reels, Nan Zheng, Bryan Duggan

Conference papers

In this paper we describe a system that uses a corpus of 864 traditional Irish reels as input into an algorithm that composes new tunes. The system performs a structural analysis of the tunes in the corpus and also counts n-gram note sequences in the tunes. It then recombines n-gram note sequences together in structures from the corpus to generate new tunes. We further present our evaluation of the generated tunes as performed by 29 domain experts.

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Opensourcepacs: An Extensible Infrastructure For Medical Image Management, John David N. Dionisio, Alex A T Bui, Craig Morioka, David B. Johnson, Usha Sinha, Siamak Ardekani, Ricky K. Taira, Denise R. Aberle, Suzie El-Saden, Hooshang Kangarloo Jan 2007

Opensourcepacs: An Extensible Infrastructure For Medical Image Management, John David N. Dionisio, Alex A T Bui, Craig Morioka, David B. Johnson, Usha Sinha, Siamak Ardekani, Ricky K. Taira, Denise R. Aberle, Suzie El-Saden, Hooshang Kangarloo

Computer Science Faculty Works

The development of comprehensive picture archive and communication systems (PACS) has mainly been limited to proprietary developments by vendors, though a number of freely available software projects have addressed specific image management tasks. The openSourcePACS project aims to provide an open source, common foundation upon which not only can a basic PACS be readily implemented, but to also support the evolution of new PACS functionality through the development of novel imaging applications and services. openSourcePACS consists of four main software modules: 1) image order entry, which enables the ordering and tracking of structured image requisitions; 2) an agent-based image server …

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A Critical Review On Electromagnetic Precursors And Earthquake Prediction, Levent Sevgi̇ Jan 2007

A Critical Review On Electromagnetic Precursors And Earthquake Prediction, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Seismo-electromagnetic precursory-based earthquake prediction studies are criticized in terms of their scientific content, problem complexity, signal excitation and propagation, causal relations with earthquakes, and public awareness and expectations. One aim is to trigger a new debate on this hot topic in the Electromagnetic Society.

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A Variable Gain Pi Controller Used For Speed Control Of A Direct Torque Neuro Fuzzy Controlled Induction Machine Drive, A. Miloudi, Eid A. Al-Radadi, Azeddine Draou Jan 2007

A Variable Gain Pi Controller Used For Speed Control Of A Direct Torque Neuro Fuzzy Controlled Induction Machine Drive, A. Miloudi, Eid A. Al-Radadi, Azeddine Draou

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an original variable gain PI (VGPI) controller for speed control of a direct torque neuro fuzzy controlled (DTNFC) induction motor drive. First, a VGPI speed controller is designed to replace the classical PI controller in a conventional direct torque controlled induction motor drive. Its simulated performances are then compared to those of a classical PI controller. Then, a direct torque neuro fuzzy control (DTNFC) for a voltage source PWM inverter fed induction motor drive is presented. This control scheme uses the stator flux amplitude and the electromagnetic torque errors through an adaptive NF inference system (ANFIS) to …

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Data Mining And Costas Arrays, Konstantinos Drakakis Jan 2007

Data Mining And Costas Arrays, Konstantinos Drakakis

Turkish Journal of Electrical Engineering and Computer Sciences

Costas arrays are used in RADAR (and SONAR) engineering to represent frequency-hopping patterns that optimize the RADAR's performance. In this work, using all available Costas arrays up to and including order 26, as well as data mining techniques, we investigate how the Costas property and the balance of signs in the difference triangle of a permutation are related. Our conclusion is that there is sufficient evidence to believe that the mechanism responsible for the formation of Costas arrays changes from low to high orders.

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Securitycom: A Multi-Player Game For Researching And Teaching Information Security Teams, Douglas P. Twitchell Jan 2007

Securitycom: A Multi-Player Game For Researching And Teaching Information Security Teams, Douglas P. Twitchell

Journal of Digital Forensics, Security and Law

A major portion of government and business organizations’ attempts to counteract information security threats is teams of security personnel. These teams often consist of personnel of diverse backgrounds in specific specialties such as network administration, application development, and business administration, resulting in possible conflicts between security, functionality, and availability. This paper discusses the use of games to teach and research information security teams and outlines research to design and build a simple, team-oriented, configurable, information security game. It will be used to study how information security teams work together to defend against attacks using a multi-player game, and to study …

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A Gnu Radio Based Software-Defined Radar, Lee K. Patton Jan 2007

A Gnu Radio Based Software-Defined Radar, Lee K. Patton

Browse all Theses and Dissertations

GNU Radio is an open source software-defined radio project, and the Universal Software Radio Peripheral (USRP) is hardware designed specifically for use with GNU Radio. Together, these two technologies have been used to implement very sophisticated, yet low cost, software-defined radios. Since software-defined radio and software-defined radar are really one in the same technologies, it stands to reason that GNU Radio and the USRP could be utilized to form a low cost radar sensor. In this thesis, we discuss the design of a prototype software-defined radar, built using the open source GNU Radio and open specification USRP projects. The prototype …

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Algan/Gan Hemt Topology Investigation Using Measured Data And Device Modeling, Derrick Langley Jan 2007

Algan/Gan Hemt Topology Investigation Using Measured Data And Device Modeling, Derrick Langley

Browse all Theses and Dissertations

Investigation has been done on procedure, development, and verification of transistor topology for Aluminum-Gallium Nitride/Gallium Nitride (AlGaN/GaN) High-Electron Mobility Transistor (HEMTs). To date various models have been published that address modeling issues dealing with AlGaN/GaN HEMTs. Many models rely on analytic parameter solutions to help define model behavior. In order to find an optimum transistor at X-band frequency, 8-12 Gigahertz (GHz), layout, testing, modeling and simulation was conducted on various transistor topologies. Theoretical and experimental analysis has been completed for device operating point selection in measurement and modeling to account for self-heating and radio frequency (RF) dispersion effects. The model …

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Investigation Of Cylindrically-Conformed Four-Arm Spiral Antennas, Douglas J. Glass Jan 2007

Investigation Of Cylindrically-Conformed Four-Arm Spiral Antennas, Douglas J. Glass

Browse all Theses and Dissertations

A four-arm spiral antenna offers broadband frequency response, wide beamwidths, reduced size compared to other antenna designs, and the ability to determine the relative direction of an incident signal with appropriate mode-forming. The reduced overall area projection of the four-arm spiral antenna compared to other antenna designs and the ability to be manufactured in a planar format allows the antenna to reside within an Unmanned Air Vehicle (UAV) fuselage. This thesis investigates the effects of cylindrically-conforming two different designs of a four-arm spiral antenna to reside within the fuselage of a medium-sized UAV. Theoretical predictions of antenna performance were created …

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Improved Thresholding Technique For The Monobit Receiver, Jonathan Gordon Buck Jan 2007

Improved Thresholding Technique For The Monobit Receiver, Jonathan Gordon Buck

Browse all Theses and Dissertations

Wideband digital receivers typically use a very high sampling rate to capture a signal for near real-time processing. Very robust digital techniques, like the Monobit FFT technique, have been developed to provide near real-time processing of captured timedomain signals. Most of these techniques trade accuracy for processing speed by approximating computationally complex mathematical operations. The approximation sometimes makes it difficult to detect multiple signals if the difference between their amplitudes is more than a few dB. This thesis presents a dynamic thresholding technique for multi-tone signal detection. The technique is based on setting an allowable ratio between the magnitude of …

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Parameterizable Channelized Wideband Digital Receiver For High Update Rate, Peter E. Buxa Jan 2007

Parameterizable Channelized Wideband Digital Receiver For High Update Rate, Peter E. Buxa

Browse all Theses and Dissertations

Wideband digital receivers are important components used prevalently by the United States Air Force for many modern electronic warfare systems. Currently, many digital receiver architectures are designed for a specific mission requirement and are not parameterizable, modular, or reusable for varying mission requirements. Also, many designs are technology, platform, and vendor dependent which make upgrading existing fielded systems costly and difficult. Additionally, current wideband FFT-based digital receivers must wait until a number of samples equal to the size of the FFT are collected before spectral information can be updated. Achieving a high spectral update rate is important for the accurate …

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Change Detection Methods For Hyperspectral Imagery, Karmon Marie Vongsy Jan 2007

Change Detection Methods For Hyperspectral Imagery, Karmon Marie Vongsy

Browse all Theses and Dissertations

This thesis studies the detection of changes using hyperspectral images. Change Detection (CD) is the process of identifying and examining temporal and spectral changes in signals. Detection and analysis of change provide valuable information of possible transformations in a scene. Hyperspectral imaging (HSI) sensors are capable of collecting data at hundreds of narrow spectral bands. Such sensors provide high-resolution spatial and spectrally rich information that can be exploited for CD. This work develops and implements various CD algorithms for detection of changes using Hyperspectral images. The main objectives are to study and develop different HSI change detection algorithms. The explored …

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Development Of An Intelligent Autonomous Coffee Maker, Nicholas J. Vanderpool Jan 2007

Development Of An Intelligent Autonomous Coffee Maker, Nicholas J. Vanderpool

Browse all Theses and Dissertations

Using Intelligent Control Methodology Home coffee machines have improved over time with the addition of features such as self-activating timers and crude temperature controlled heating elements. However, home coffee brewer development has stagnated and has yet to achieve full automation status. Present coffee machines leave the user burdened with the mundane and messy task of preparing the coffee maker every time. Also, should the user decide to prepare less than an entire pot, he/she must estimate the correct amount of water and coffee to add. This can lead to a weak or strong brew, giving undesirable results. In order to …

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