Coupled Photonic Crystal Micro-Cavities With Ultra-Low Threshold Power For Stiumulated Raman Scattering,
2011
Old Dominion University
Coupled Photonic Crystal Micro-Cavities With Ultra-Low Threshold Power For Stiumulated Raman Scattering, Qiang Liu, Zhengbiao Ouyang, Sacharia Albin
Electrical & Computer Engineering Faculty Publications
We propose coupled cavities to realize a strong enhancement of the Raman scattering. Five sub cavities are embedded in the photonic crystals. Simulations through finite-difference time-domain (FDTD) method demonstrate that one cavity, which is used to propagate the pump beam at the optical-communication wavelength, has a Q factor as high as 1.254 × 108 and modal volume as small as 0.03μm3 (0.3192(λ/n)3). These parameters result in ultra-small threshold lasing power ~17.7nW and 2.58nW for Stokes and anti-Stokes respectively. The cavities are designed to support the required Stokes and anti-Stokes modal spacing in silicon. The proposed structure …
Advanced Linear Identification Techniques For Signal Processing And Digital Video Broadcasting,
2011
Louisiana State University and Agricultural and Mechanical College
Advanced Linear Identification Techniques For Signal Processing And Digital Video Broadcasting, Xiaoyu Feng
LSU Doctoral Dissertations
Linear identification technique is to linearly embed a piece of unique information into digital media data for the purpose of satisfying specific demands such as identification, annotation, and copyright, etc. We need to consider the quantity and the quality of identification data to be embedded as well as the corresponding interference to the original subject signal. However, there exist no generalized computationally-efficient optimization techniques for linear identification up to now. Therefore, in this dissertation work, we try to theoretically investigate the advanced linear identification techniques and combat the tradeoff problems between the quality of the embedded identification data and the …
Communication-Constrained Feedback Stability And Multi-Agent System Consensusability In Networked Control Systems,
2011
Louisiana State University and Agricultural and Mechanical College
Communication-Constrained Feedback Stability And Multi-Agent System Consensusability In Networked Control Systems, Laurentiu Dan Marinovici
LSU Doctoral Dissertations
With the advances in wireless communication, the topic of Networked Control Systems (NCSs) has become an interesting research subject. Moreover, the advantages they offer convinced companies to implement and use data networks for remote industrial control and process automation. Data networks prove to be very efficient for controlling distributed systems, which would otherwise require complex wiring connections on large or inaccessible areas. In addition, they are easier to maintain and more cost efficient. Unfortunately, stability and performance control is always going to be affected by network and communication issues, such as band-limited channels, quantization errors, sampling, delays, packet dropouts or …
Phase Noise In Cmos Phase-Locked Loop Circuits,
2011
Louisiana State University and Agricultural and Mechanical College
Phase Noise In Cmos Phase-Locked Loop Circuits, Yang Liu
LSU Doctoral Dissertations
Phase-locked loops (PLLs) have been widely used in mixed-signal integrated circuits. With the continuously increasing demand of market for high speed, low noise devices, PLLs are playing a more important role in communications. In this dissertation, phase noise and jitter performances are investigated in different types of PLL designs. Hot carrier and negative bias temperature instability effects are analyzed from simulations and experiments. Phase noise of a CMOS phase-locked loop as a frequency synthesizer circuit is modeled from the superposition of noises from its building blocks: voltage-controlled oscillator, frequency divider, phase-frequency detector, loop filter and auxiliary input reference clock. A …
Advanced Signal Processing Techniques For Single Trial Electroencephalography Signal Classification For Brain Computer Interface Applications,
2010
University of South Florida
Advanced Signal Processing Techniques For Single Trial Electroencephalography Signal Classification For Brain Computer Interface Applications, Kun Li
USF Tampa Graduate Theses and Dissertations
Brain Computer Interface (BCI) is a direct communication channel between brain and computer. It allows the users to control the environment without the need to control muscle activity [1-2]. P300-Speller is a well known and widely used BCI system that was developed by Farwell and Donchin in 1988 [3]. The accuracy level of the P300-BCI Speller as measured by the percent of communicated characters correctly identified by the system depends on the ability to detect the P300 event related potential (ERP) component among the ongoing electroencephalography (EEG) signal. Different techniques have been tested to reduce the number of trials needed …
A Study On Prospects For The Evolution Of Maritime Traffic Management Systems Taking Into Account E-Navigation,
2010
World Maritime University
A Study On Prospects For The Evolution Of Maritime Traffic Management Systems Taking Into Account E-Navigation, Kwang An
World Maritime University Dissertations
No abstract provided.
Analysis Of Factors Affecting Technological Innovativeness In Engineering Enterprises In Tanzania,
2010
Department of Mechanical and Industrial Engineering, College of Engineering and Technology, University of Dar es Salaam, P.O. Box 35131, Dar es Salaam
Analysis Of Factors Affecting Technological Innovativeness In Engineering Enterprises In Tanzania, Emanuel Mjema
Tanzania Journal of Engineering and Technology (TJET)
This paper discusses the technological innovativeness in engineering enterprises in Tanzania and analyses the factors affecting the innovativeness. It starts by analyzing various concepts regarding innovation, then analyzed from documentary review factors affecting innovativeness and then analyzed the innovativeness in Tanzanian enterprises. From the documentary review it was learnt that the following key factors influence technological innovativeness: Existence of innovation management; Existence of market to absorb the products of innovation; Existence of partnership between the universities and the firms; Existence of positive culture and politics towards innovation; The government playing its role to influence innovation; Existence of the right knowledge; …
Adaptive Routing Scheme For Emerging Wireless Ad Hoc Networks,
2010
Missouri University of Science and Technology
Adaptive Routing Scheme For Emerging Wireless Ad Hoc Networks, Behdis Eslamnour, Sarangapani Jagannathan
Electrical and Computer Engineering Faculty Research & Creative Works
Node mobility causes fading wireless channels, which in turn renders topology changes in emerging wireless ad hoc networks. in this paper, on-line estimators and Markov models are utilized to estimate fading channel conditions. using the estimated channel conditions as well as queue occupancy, available energy and link delay, approximate dynamic programming (ADP) techniques are utilized to find dynamic routes, while solving discrete-time Hamilton-Jacobi-Bellman (HJB) equation forward-in-time for route cost in multichannel multi-interface networks. the performance of the proposed load balancing method in the presence of fading channels and the performance of the optimal route selection approach for multichannel multi-interface wireless …
Time-Varying Harmonic Analyzer Prototype,
2010
Universidade Federal de Juiz de Fora
Time-Varying Harmonic Analyzer Prototype, Diego F. Fabri, Carlos H. N. Martins, Leandro R. M. Silva, Carlos A. Duque
University Faculty Publications and Creative Works
This paper presents a time-varying harmonic analyzer based on the Sliding Window DFT implemented on a DSP platform. The harmonic decomposition is carried out using the TMS320F28027 digital signal processor, and the samples of the decomposed signal are sent to a PC based computer using serial interface. Several real cases are analyzed, revealing the time-varying behavior of the harmonic component. Different from commercial harmonic analyzer, the prototype presented in this paper uses a different way to visualize the harmonic components, based on time decomposition approach. This new visualization of time-varying harmonics might help engineers and researchers to develop new insights …
Time-Varying Harmonic Analyzer Prototype,
2010
Universidade Federal de Juiz de Fora
Time-Varying Harmonic Analyzer Prototype, Diego F. Fabri, Carlos H. N. Martins, Leandro R. M. Silva, Carlos A. Duque
University Faculty Publications and Creative Works
This paper presents a time-varying harmonic analyzer based on the Sliding Window DFT implemented on a DSP platform. The harmonic decomposition is carried out using the TMS320F28027 digital signal processor, and the samples of the decomposed signal are sent to a PC based computer using serial interface. Several real cases are analyzed, revealing the time-varying behavior of the harmonic component. Different from commercial harmonic analyzer, the prototype presented in this paper uses a different way to visualize the harmonic components, based on time decomposition approach. This new visualization of time-varying harmonics might help engineers and researchers to develop new insights …
Design Concepts Of Terahertz Quantum Cascade Lasers: Proposal For Terahertz Laser Efficiency Improvements,
2010
NCN, Purdue University
Design Concepts Of Terahertz Quantum Cascade Lasers: Proposal For Terahertz Laser Efficiency Improvements, Tillmann Kubis, Saumitra Raj Mehrotra, Gerhard Klimeck
Birck and NCN Publications
Conceptual disadvantages of typical resonant phonon terahertz quantum cascade lasers THz-QCLs are analyzed. Alternative designs and their combination within a concrete device proposal are discussed to improve the QCL performance. The improvements are 1 indirect pumping of the upper laser level, 2 diagonal optical transitions, 3 complete electron thermalization, and 4 materials with low effective electron masses. The nonequilibrium Green’s function method is applied to predict stationary electron transport and optical gain. The proposed THz-QCL shows a higher optical gain, a lower threshold current, and a higher operation temperature. Alloy disorder scattering can worsen the QCL performance.
A Memory Saving Vector Fast Multipole Algorithm For Solving The Augmented Efie,
2010
Missouri University of Science and Technology
A Memory Saving Vector Fast Multipole Algorithm For Solving The Augmented Efie, Yang G. Liu, Weng Cho Chew, Li (Lijun) Jun Jiang
Electrical and Computer Engineering Faculty Research & Creative Works
An augmented EFIE (A-EFIE)[9], [10] has been proposed to separate the contributions of the vector potential and the scalar potential for avoiding the imbalance at low frequencies. The corresponding low frequency fast multipole algorithm (LFFMA) [11] was also developed for solving the A-EFIE. Instead of the factorization of the scalar Green's function by using scalar addition theorem in the LF-FMA, we adopt the vector addition theorem for the factorization of the dyadic Green's function to realize memory savings. We are to develop a vector fast multipole algorithm for solving the A-EFIE. © 2010 IEEE.
A High-Quality Mach-Zehnder Interferometer Fiber Sensor By Femtosecond Laser One-Step Processing,
2010
Missouri University of Science and Technology
A High-Quality Mach-Zehnder Interferometer Fiber Sensor By Femtosecond Laser One-Step Processing, Longjiang Zhao, Lan Jiang, Sumei Wang, Hai Xiao, Yongfeng Lu, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
During new fiber sensor development experiments, an easy-to-fabricate simple sensing structure with a trench and partially ablated fiber core is fabricated by using an 800 nm 35 fs 1 kHz laser. It is demonstrated that the structure forms a Mach-Zehnder interferometer (MZI) with the interference between the laser light passing through the air in the trench cavity and that in the remained fiber core. The fringe visibilities are all more than 25 dB. The transmission spectra vary with the femtosecond (fs) laser ablation scanning cycle. The free spectral range (FSR) decreases as the trench length increases. The MZI structure is …
Integrated Freestanding Single-Crystal Silicon Nanowires: Conductivity And Surface Treatment,
2010
Marquette University
Integrated Freestanding Single-Crystal Silicon Nanowires: Conductivity And Surface Treatment, Chung-Hoon Lee, Clark Ritz, Minghuang Huang, Michael Ziwisky, Robert Blise, Max Lagally
Electrical and Computer Engineering Faculty Research and Publications
Integrated freestanding single-crystal silicon nanowires with typical dimension of 100 nm × 100 nm × 5 µm are fabricated by conventional 1:1 optical lithography and wet chemical silicon etching. The fabrication procedure can lead to wafer-scale integration of silicon nanowires in arrays. The measured electrical transport characteristics of the silicon nanowires covered with/without SiO2 support a model of Fermi level pinning near the conduction band. The I–V curves of the nanowires reveal a current carrier polarity reversal depending on Si–SiO2 and Si–H bonds on the nanowire surfaces
Extraction Of Contact Resistance In Carbon Nanofiber Via Interconnects With Varying Lengths,
2010
Santa Clara University
Extraction Of Contact Resistance In Carbon Nanofiber Via Interconnects With Varying Lengths, Ken Li, Patrick Wilhite, Vinit Khera, Shoba Krishnan, Xuhui Sun, Cary Y. Yang
Electrical and Computer Engineering
A method to extract the contact resistance and bulk resistivity of vertically grown carbon nanofibers (CNFs) or similar one-dimensional nanostructures is described. Using a silicon-compatible process to fabricate a terrace test structure needed for the CNF length variation, the contact resistance is extracted by measuring in situ the resistances of individual CNFs with different lengths and within a small range of diameters using a nanoprober inside a scanning electron microscope. Accurate determination of contact resistances for various combinations of catalysts and underlayer metals can lead to eventual optimization of materials’ growth and device fabrication processes for CNF via interconnects.
Indirect Adaptive Control Of An Active Filter Using Echo State Networks,
2010
Missouri University of Science and Technology
Indirect Adaptive Control Of An Active Filter Using Echo State Networks, Jing Dai, Ganesh K. Venayagamoorthy, Ronald G. Harley, Keith A. Corzine
Electrical and Computer Engineering Faculty Research & Creative Works
An active filter is a power electronic device used in a power system to decrease "harmonic current pollution" caused by nonlinear loads. the Echo State Network (ESN) has been widely used as an effective system identifier with much faster training speed than the other Recurrent Neural Networks (RNNs). However, only a few attempts have been made to use an ESN as a system controller. as the first attempt to use an ESN in indirect NeuroControl, this paper proposes an indirect adaptive NeuroControl scheme using two ESNs to control an active filter in a multiple-reference frame. as the first step in …
High Impedance Arc Fault Detection In A Manhole Environment.,
2010
East Tennessee State University
High Impedance Arc Fault Detection In A Manhole Environment., Thomas Arthur Cooke
Electronic Theses and Dissertations
The scope of this thesis was to develop a prototype high-impedance arc detection system that a utility worker could use as an early warning system while working in a manhole environment. As part of this system sensors and algorithms were developed to increase the sensitivity of detecting an arc while ignoring loads that can give false positive signatures for arcing. The latest technology was used to repeat measurements performed in previous research from decades ago that lacked in sampling speed and amplitude resolution. Several types of arcs were produced and analyzed so to establish a library of various waveform and …
New Handheld Emissions Detector For Pinpointing The Location Of Inadvertently Energized Objects In Urban Environments.,
2010
East Tennessee State University
New Handheld Emissions Detector For Pinpointing The Location Of Inadvertently Energized Objects In Urban Environments., Kermit O. Phipps
Electronic Theses and Dissertations
The power distribution infrastructure in the United States is deteriorating at a rapid rate exposing infrastructure wiring and creating potential shock hazards. Periodic road and sidewalk maintenance projects can also expose wiring and create energized objects. In urban settings inadvertently energized objects include: lamp posts, bus shelters, metal street curbs, sign posts, transformer vaults, and manhole covers as well as concrete and asphalt pavement. Every year electric shocks occur when people and domestic animals (such as dogs and cats) make incidental contact with these energized objects. In very rare cases the shocks from these contacts are lethal. Through current personal …
Distributed Grid Intelligence For Future Microgrid With Renewable Sources And Storage,
2010
Missouri University of Science and Technology
Distributed Grid Intelligence For Future Microgrid With Renewable Sources And Storage, Fanjun Meng, Ravi Akella, Mariesa L. Crow, Bruce Mcmillin
Electrical and Computer Engineering Faculty Research & Creative Works
The FREEDM microgrid is a smart grid solution with Distributed Grid Intelligence (DGI) to efficiently manage the power distribution and storage of renewable energy. within the FREEDM system, DGI applies distributed control method in a unique way to achieve feasible load balancing in microgrid by migrating power between renewable energy generation and storage at each node. This paper presents the key aspects in implementing such a scheme and outlines the preliminary results obtained by integrating the proposed methodology. the results demonstrate the potential benefits of adopting DGI control on a microgrid.
A Novel Phase-Locked-Loop And Its Application In Statcom System,
2010
Missouri University of Science and Technology
A Novel Phase-Locked-Loop And Its Application In Statcom System, L. Shi, Mariesa L. Crow
Electrical and Computer Engineering Faculty Research & Creative Works
Phase-Locked-Loop (PLL) plays important role in grid connected power electronics system. a good PLL system can detect the grid phase angle and frequency fast and accurately, and additionally it can extract the positive sequence exactly. in real applications, source signal (voltage or current) usually includes harmonic distortion, unbalanced components. Conventional PLL strategy cannot solve the unbalanced and harmonic distortion problems. Different PLL solutions are proposed in literature in recent years. the general considerations for these different approaches are to design positive sequence estimator to eliminate the negative sequence components and use filters to filter out the higher order harmonic distortions. …
