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Full-Text Articles in Computer Engineering

Self-Organizing Microstructures Orientation Control In Femtosecond Laser Patterning On Silicon Surface, Pengjun Liu, Lan Jiang, Jie Hu, Shuai Zhang, Yongfeng Lu Jul 2014

Self-Organizing Microstructures Orientation Control In Femtosecond Laser Patterning On Silicon Surface, Pengjun Liu, Lan Jiang, Jie Hu, Shuai Zhang, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Self-organizing rippled microstructures are induced on silicon surface by linearly polarized femtosecond laser pulses. At a near threshold fluence, it is observed that ripple orientation is co-determined by the laser polarization direction and laser scanning parameters (scanning direction and scanning speed) in surface patterning process. Under fixed laser polarization, the ripple orientation can be controlled to rotate by about 40° through changing laser scanning parameters. In addition, it is also observed that the ripple morphology is sensitive to the laser scanning direction, and it is an optimal choice to obtain ordered ripple structures when the angle between laser scanning and …


Human Brain Networks: Spiking Neuron Models, Multistability, Synchronization, Thermodynamics, Maximum Entropy Production, And Anesthetic Cascade Mechanisms, Wassim H. Haddad, Qing Hui, James M. Bailey Jul 2014

Human Brain Networks: Spiking Neuron Models, Multistability, Synchronization, Thermodynamics, Maximum Entropy Production, And Anesthetic Cascade Mechanisms, Wassim H. Haddad, Qing Hui, James M. Bailey

Department of Electrical and Computer Engineering: Faculty Publications

Advances in neuroscience have been closely linked to mathematical modeling beginning with the integrate-and-fire model of Lapicque and proceeding through the modeling of the action potential by Hodgkin and Huxley to the current era. The fundamental building block of the central nervous system, the neuron, may be thought of as a dynamic element that is “excitable”, and can generate a pulse or spike whenever the electrochemical potential across the cell membrane of the neuron exceeds a threshold. A key application of nonlinear dynamical systems theory to the neurosciences is to study phenomena of the central nervous system that exhibit nearly …


Anisotropy Modulations Of Femtosecond Laser Pulse Induced Periodic Surface Structures On Silicon By Adjusting Double Pulse Delay, Weina Han, Lan Jiang, Xiaowei Li, Qingsong Wang, Hao Li, Yongfeng Lu Jun 2014

Anisotropy Modulations Of Femtosecond Laser Pulse Induced Periodic Surface Structures On Silicon By Adjusting Double Pulse Delay, Weina Han, Lan Jiang, Xiaowei Li, Qingsong Wang, Hao Li, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

We demonstrate that the polarization-dependent anisotropy of the laser-induced periodic surface structure (LIPSS) on silicon can be adjusted by designing a femtosecond laser pulse train (800 nm, 50 fs, 1 kHz). By varying the pulse delay from 100 to 1600 fs within a double pulse train to reduce the deposited pulse energy, which weakens the directional surface plasmon polarition (SPP)-laser energy coupling based on the initial formed ripple structure, the polarization-dependent geometrical morphology of the LIPSS evolves from a nearly isotropic circular shape to a somewhat elongated elliptical shape. Meanwhile, the controllable anisotropy of the two-dimensional scanned-line widths with different …


Processing Of Monolayer Materals Vlanterfacial Reactions, Peter Werner Sutter, Eli Anguelova Sutter May 2014

Processing Of Monolayer Materals Vlanterfacial Reactions, Peter Werner Sutter, Eli Anguelova Sutter

Department of Electrical and Computer Engineering: Faculty Publications

A method of forming and processing of graphene is disclosed based on exposure and selective intercalation of the partially graphene-covered metal Substrate with atomic or molecular intercalation species such as oxygen (O) and nitrogen oxide (NO). The process of intercalation lifts the strong metal carbon coupling and restores the characteristic Dirac behav ior of isolated monolayer graphene. The interface of graphene with metals or metal-decorated substrates also provides for controlled chemical reactions based on novel functionality of the confined space between a metal Surface and a graphene sheet.


Polarization-Coupled Ferroelectric Unpolarunction Memory And Energy Storage Device, Mathias M. Schubert, Tino Hofmann, Venkata Rao Voora Apr 2014

Polarization-Coupled Ferroelectric Unpolarunction Memory And Energy Storage Device, Mathias M. Schubert, Tino Hofmann, Venkata Rao Voora

Department of Electrical and Computer Engineering: Faculty Publications

A memory device is provided. The memory device includes a plurality of memory cells and a controller to write data to and read data from the memory cells. Each memory cell includes a first semiconductor material having a spontaneous polarization, a resistive ferroelectric material having a switchable spontaneous polarization, and a second semiconductor material having a spontaneous polarization, the resistive ferroelectric material being positioned between and in contact with the first and second semiconductor materials. The memory device can be configured to store energy that can be released by applying a voltage pulse to the memory device.


Flame-Enhanced Laser-Induced Breakdown Spectroscopy, L. Liu, S. Li, X. N. He, X. Huang, C. F. Zhang, L. S. Fan, M. X. Wang, Y. S. Zhou, K. Chen, L. Jiang, J. F. Silvain, Yongfeng Lu Apr 2014

Flame-Enhanced Laser-Induced Breakdown Spectroscopy, L. Liu, S. Li, X. N. He, X. Huang, C. F. Zhang, L. S. Fan, M. X. Wang, Y. S. Zhou, K. Chen, L. Jiang, J. F. Silvain, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Flame-enhanced laser-induced breakdown spectroscopy (LIBS) was investigated to improve the sensitivity of LIBS. It was realized by generating laser-induced plasmas in the blue outer envelope of a neutral oxy-acetylene flame. Fast imaging and temporally resolved spectroscopy of the plasmas were carried out. Enhanced intensity of up to 4 times and narrowed full width at half maximum (FWHM) down to 60% for emission lines were observed. Electron temperatures and densities were calculated to investigate the flame effects on plasma evolution. These calculated electron temperatures and densities showed that high-temperature and low-density plasmas were achieved before 4 μs in the flame environment, …


Relationship Between Photofixed Condensate, Effluent And Bulk Composition Of Several Common Rtv Materials, Fen Zhou Hanrahan, Natale J. Ianno Apr 2014

Relationship Between Photofixed Condensate, Effluent And Bulk Composition Of Several Common Rtv Materials, Fen Zhou Hanrahan, Natale J. Ianno

Department of Electrical and Computer Engineering: Faculty Publications

Raman spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy are employed to analyze the bulk compositions of five kinds of Room Temperature Vulcanized (RTV) silicones (CV2568, RTV566, DC93-500, SCV2590 and SCV2590-2) that are commonly employed in orbiting spacecraft. It is found that polydimethylsiloxane (PDMS), silicon dioxide, Tetra-n-propylsilicate (NPS), silicic acid, tetraethyl orthosilicate, and trimethylsilanol are contained in all of them. The outgassing products from those silicones are characterized by FTIR. By comparing the position of the peaks, it is found that the outgassing products of each material are PDMS and NPS which are consistent with the compositions of samples determined with …


Contrast Enhancement Using Silica Microspheres In Coherent Anti-Stokes Raman Spectroscopic Imaging, X. Huang, X. N. He, W. Xiong, Y. Gao, L. J. Jiang, Li Liu, Y. S. Zhou, L. Jiang, J. F. Silvain, Yongfeng Lu Feb 2014

Contrast Enhancement Using Silica Microspheres In Coherent Anti-Stokes Raman Spectroscopic Imaging, X. Huang, X. N. He, W. Xiong, Y. Gao, L. J. Jiang, Li Liu, Y. S. Zhou, L. Jiang, J. F. Silvain, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Coherent anti-Stokes Raman scattering (CARS) microscopy is a powerful imaging technique that can provide chemical information of organic and nonorganic materials through vibrational spectroscopy. However, its contrast is not sufficient for monitoring thin film materials. In this study, silica microspheres were employed for enhancing the signal contrast in CARS imaging. One layer of optically transparent silica microspheres was self-assembled onto polymer grating samples to enhance the CARS signals. The highest contrast enhancement factor of 12.5 was achieved using 6.1-μm-diameter microspheres. Finite-difference timedomain method (FDTD) simulation was conducted to simulate the contrast enhancement with silica microspheres of different diameters.


Fiber-Optic Temperature Sensor Using A Fabry–Pérot Cavity Filled With Gas Of Variable Pressure, Yujie Lu, Ming Han, Jiajun Tian Jan 2014

Fiber-Optic Temperature Sensor Using A Fabry–Pérot Cavity Filled With Gas Of Variable Pressure, Yujie Lu, Ming Han, Jiajun Tian

Department of Electrical and Computer Engineering: Faculty Publications

We report a high-temperature fiber-optic sensor based on measuring the spectral fringes of a Fabry–Pérot (FP) cavity on a microstructure fiber (MF) when the gas pressure in the cavity is varied through the holes in the MF. Theoretical analysis shows that the absolute temperature can be deduced from the slope of the spectral shift versus pressure curve, which requires no calibration and is insensitive to the FP cavity length variations. For demonstration, we fabricated a miniature sensor whose FP cavity is formed by sandwiching a fuse-silica tube between a side-hole MF and a solid-core fiber. Using the holes in the …


An Interconnection And Damping Assignment Passivity-Based Controller For A Dc–Dc Boost Converter With A Constant Power Load, Jianwu Zeng, Zhe Zhang, Wei Qiao Jan 2014

An Interconnection And Damping Assignment Passivity-Based Controller For A Dc–Dc Boost Converter With A Constant Power Load, Jianwu Zeng, Zhe Zhang, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes an adaptive interconnection and damping assignment (IDA) passivity-based controller (PBC) with a complementary proportional integral (PI) controller for dc–dc boost converters with constant power loads (CPLs). The plant is modeled as a port-controlled Hamiltonian system (PCHS). A virtual circuit that interprets the parameters of the PCHS is then derived to determine the parameters of the IDA-PBC for the system to work in the underdamping, critical-damping, and overdamping modes. Moreover, a complementary PI controller is designed to eliminate the steady-state output voltage error of the IDA-PBC caused by the load variation. Simulation studies are carried out inMATLAB/Simulink to …


An Effective Heat Propagation Path-Based Online Adaptive Thermal Model For Igbt Modules, Ze Wang, Wei Qiao, Bo Tian, Liyan Qu Jan 2014

An Effective Heat Propagation Path-Based Online Adaptive Thermal Model For Igbt Modules, Ze Wang, Wei Qiao, Bo Tian, Liyan Qu

Department of Electrical and Computer Engineering: Faculty Publications

The information of junction temperature is crucial for operation management of IGBT modules. In practice, junction temperature is typically estimated by using an electrothermal model. IGBT modules are subject to various aging processes during operation, some of which, e.g. substrate solder crack, changes the thermal impedance of an IGBT module. However, in the literature little work has included the aging effects into online thermal behavior modeling of IGBT modules. This paper proposes an Effective Heat Propagation Path (EHPP)-based online adaptive thermal model for IGBT modules, where the EHPP is proposed to quantify the impact of substrate solder cracks on the …


An Isolated Multiport Dc–Dc Converter For Simultaneous Power Management Of Multiple Different Renewable Energy Sources, Jianwu Zeng, Wei Qiao, Liyan Qu, Yanping Jiao Jan 2014

An Isolated Multiport Dc–Dc Converter For Simultaneous Power Management Of Multiple Different Renewable Energy Sources, Jianwu Zeng, Wei Qiao, Liyan Qu, Yanping Jiao

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes a new isolated multiport dc–dc converter for simultaneous power management of multiple renewable energy sources, which can be of different types and capacities. The proposed dc–dc converter only uses one controllable switch in each port to which a source is connected. Therefore, it has the advantages of simple topology and minimum number of power switches. A general topology of the proposed converter is first introduced. Its principle and operation are then analyzed. The proposed converter is applied for simultaneous maximum power point tracking (MPPT) control of a wind/solar hybrid generation system consisting of one wind turbine generator …


Evaluation Of Ann Estimation-Based Mppt Control For A Dfig Wind Turbine, Chun Wei, Liyan Qu, Wei Qiao Jan 2014

Evaluation Of Ann Estimation-Based Mppt Control For A Dfig Wind Turbine, Chun Wei, Liyan Qu, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes an artificial neuronal network (ANN) estimation-based wind speed sensolress MPPT algorithm for wind turbines equipped with doubly-fed induction generators (DFIG). The ANN is designed to produce the optimal control signal for the DFIG power or speed controller. The optimal parameters of the ANN are determined by using a particle swarm optimization (PSO) algorithm. A 3.6 MW DFIG wind turbine is simulated in PSCAD to evaluate and compare the proposed MPPT method with the traditional tip speed ratio (TSR) and turbine power profile-based MPPT methods in both the speed control and power control modes in variable wind speed …


A Flux Vector-Based Discrete-Time Direct Torque Control For Salient-Pole Permanent-Magnet Synchronous Generators, Zhe Zhang, Yue Zhao, Jianwu Zeng, Wei Qiao Jan 2014

A Flux Vector-Based Discrete-Time Direct Torque Control For Salient-Pole Permanent-Magnet Synchronous Generators, Zhe Zhang, Yue Zhao, Jianwu Zeng, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes a flux vector-based discretetime direct torque control (DTC) scheme for salient-pole permanent-magnet synchronous generators (PMSGs) used in the variable-speed, direct-drive wind energy conversion systems (WECSs). The discrete-time control law is derived from the perspective of flux space vectors and load angle with the torque and stator flux information only. The saliency of the PMSG is eliminated by the active flux concept. Compared with the existing space vector modulation (SVM)-based DTCs, the proposed scheme removes the use of PI regulators and is less dependent on the machine parameters, e.g., stator inductances and permanent-magnet flux linkage, while maintaining the …


Improved Rotor Position And Speed Estimators For Sensorless Control Of Interior Permanent-Magnet Synchronous Machines, Yue Zhao, Wei Qiao, Long Wu Jan 2014

Improved Rotor Position And Speed Estimators For Sensorless Control Of Interior Permanent-Magnet Synchronous Machines, Yue Zhao, Wei Qiao, Long Wu

Department of Electrical and Computer Engineering: Faculty Publications

Model-based rotor position/speed estimators are commonly used for sensorless control of interior permanentmagnet synchronous machines (IPMSMs) operating in the medium- and high-speed regions. A rotor position/speed estimation scheme usually contains three major parts: 1) a state observer; 2) a position estimator; and 3) a speed estimator. This paper proposes a sliding-mode observer (SMO) as the state observer to estimate the position-related system states, which are the extended electromotive force components in this paper. Then, two major contributions are made to achieve improved position and speed estimation. First, the rotor speed is estimated independently using a model reference adaptive system (MRAS)-based …


Thyristor-Controlled Switch Capacitor Placement In Large-Scale Power Systems Via Mixed Integer Linear Programming And Taylor Series Expansion, Omid Ziaee, F. Fred Choobineh Jan 2014

Thyristor-Controlled Switch Capacitor Placement In Large-Scale Power Systems Via Mixed Integer Linear Programming And Taylor Series Expansion, Omid Ziaee, F. Fred Choobineh

Department of Electrical and Computer Engineering: Faculty Publications

Allocation of flexible alternating current transmission system (FACTS) devices to an electric power transmission network may be formulated as a nonlinear mathematical program. Solving such a nonlinear program for a large transmission network is computationally very expensive, and obtaining the optimal solution may be impossible. We present a Taylor series expansion approximation of the nonlinearities of the problem and propose a mixed integer linear program (MILP) for finding the optimum location and proper settings of a Thyristor-Controlled Series Capacitor (TCSC) in an electric power network. The objective of this problem is to minimize total generation cost based on the DC …


Tunable Plasmonic And Hyperbolic Metamaterials Based On Enhanced Nonlinear Response, Christos Argyropoulos, Francesco Monticone, Nasim Mohammadi Estakhri, Andrea Alu Jan 2014

Tunable Plasmonic And Hyperbolic Metamaterials Based On Enhanced Nonlinear Response, Christos Argyropoulos, Francesco Monticone, Nasim Mohammadi Estakhri, Andrea Alu

Department of Electrical and Computer Engineering: Faculty Publications

We present here tunable and reconfigurable designs of linear and nonlinear plasmonic and hyperbolic metamaterials. Rich scattering features of multilayered composite nanoparticles are demonstrated, which include complex and exotic scattering signatures combining multiple dipolar Fano resonances and electromagnetic induced transparency (EIT) features. These dipoledipole multi-Fano scattering responses can be further tuned through altering the plasmonic properties of the concentric layers or the permittivity of the core, for instance, by the presence of nonlinearities. Strong third-order nonlinear effects, such as optical bistability, may also be induced in the scattering response of nonlinear nanoparticles due to the highly enhanced and confined fields …


Bayesian Network Prior: Network Analysis Of Biological Data Using External Knowledge, Senol Isci, Haluk Dogan, Cengizhan Ozturk, Hasan H. Otu Jan 2014

Bayesian Network Prior: Network Analysis Of Biological Data Using External Knowledge, Senol Isci, Haluk Dogan, Cengizhan Ozturk, Hasan H. Otu

Department of Electrical and Computer Engineering: Faculty Publications

Motivation: Reverse engineering GI networks from experimental data is a challenging task due to the complex nature of the networks and the noise inherent in the data. One way to overcome these hurdles would be incorporating the vast amounts of external biological knowledge when building interaction networks. We propose a framework where GI networks are learned from experimental data using Bayesian networks (BNs) and the incorporation of external knowledge is also done via a BN that we call Bayesian Network Prior (BNP). BNP depicts the relation between various evidence types that contribute to the event ‘gene interaction’ and is used …


Element Dependence Of Enhancement In Optics Emission From Laser-Induced Plasma Under Spatial Confinement, Changmao Li, Lianbo Guo, Xiangnan He, Zhongqi Hao, Xiangyou Li, Meng Shen, Xiaoyan Zeng, Yongfeng Lu Jan 2014

Element Dependence Of Enhancement In Optics Emission From Laser-Induced Plasma Under Spatial Confinement, Changmao Li, Lianbo Guo, Xiangnan He, Zhongqi Hao, Xiangyou Li, Meng Shen, Xiaoyan Zeng, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

In this study, the element dependence of spatial confinement effects in LIBS has been studied. Hemispheric cavities were used to confine laser-induced plasmas from aluminum samples with other trace elements. The enhancement factors were found to be dependent on the elements. Equations describing the element dependent enhancement factors were successfully deduced from the local thermodynamic equilibrium conditions, which have also been verified by the experimental results. Research results show that enhancement factors in LIBS with spatial confinement depend on the temperature, electron density, and compression ratio of plasmas, and vary with elements and atomic/ionic emission lines selected. Generally, emission lines …


A Low-Power Compact Nqr Based Explosive Detection System, Xinwang Zhang, Nathan Schemm, Sina Balkır, Michael W. Hoffman Jan 2014

A Low-Power Compact Nqr Based Explosive Detection System, Xinwang Zhang, Nathan Schemm, Sina Balkır, Michael W. Hoffman

Department of Electrical and Computer Engineering: Faculty Publications

Nuclear quadruple resonance (NQR) has been studied for explosive detection for years. Some prototype NQR-based detection systems have been reported, but were all designed from the laboratory perspective, with bulky sizes and high power consumption. To achieve a portable NQR-based detection system for field applications, a low-power compact system utilizing state-of-the-art semiconductor technologies is presented in this paper. Several novel circuits for the key modules are proposed, including a Class-D type power amplifier, a power multiplexing and matching network, a customized IC with integrated analog signal processing chain, and a microcontroller-based logic control unit. An advanced digital signal processor platform …


Workplace Monitoring Of Employee Health Using The Workstation Pc As A Platform, Priyankar Bhattacharjee Jan 2014

Workplace Monitoring Of Employee Health Using The Workstation Pc As A Platform, Priyankar Bhattacharjee

Department of Electrical and Computer Engineering: Faculty Publications

A country’s biggest asset is its workforce, given the fact that a healthy workforce can contribute to rapid growth of the economy. Chronic illnesses reduce productivity, are responsible for rising healthcare costs, and should be managed by the employer to reduce healthcare expenditures. This can be done through employee health and wellness programs, and well-designed health management initiatives. In addition, new information and communication technologies make it possible to monitor employee health with wearable devices and telehealth assisted surveillance techniques. This paper introduces a unique new approach to workplace healthcare monitoring, using the office workstation PC itself to monitor worker …


Clu: Co-Optimizing Locality And Utility In Thread-Aware Capacity Management For Shared Last Level Caches, Dongyuan Zhan, Hong Jiang, Sharad C. Seth Jan 2014

Clu: Co-Optimizing Locality And Utility In Thread-Aware Capacity Management For Shared Last Level Caches, Dongyuan Zhan, Hong Jiang, Sharad C. Seth

Department of Electrical and Computer Engineering: Faculty Publications

Most chip-multiprocessors nowadays adopt a large shared last-level cache (SLLC). This paper is motivated by our analysis and evaluation of state-of-the-art cache management proposals which reveal a common weakness. That is, the existing alternative replacement policies and cache partitioning schemes, targeted at optimizing either locality or utility of co-scheduled threads, cannot deliver consistently the best performance under a variety of workloads. Therefore, we propose a novel adaptive scheme, called CLU, to interactively co-optimize the locality and utility of co-scheduled threads in thread-aware SLLC capacity management. CLU employs lightweight monitors to dynamically profile the LRU (least recently used) and BIP (bimodal …


Intelligent Maximum Power Extraction Control For Wind Energy Conversion Systems Based On Online Q-Learning With Function Approximation, Chun Wei, Zhe Zhang, Wei Qiao, Liyan Qu Jan 2014

Intelligent Maximum Power Extraction Control For Wind Energy Conversion Systems Based On Online Q-Learning With Function Approximation, Chun Wei, Zhe Zhang, Wei Qiao, Liyan Qu

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes an intelligent maximum power point tracking (MPPT) algorithm for variable-speed wind energy conversion systems (WECSs) based on an online Q-learning algorithm. Instead of using the conventional Qlearning that uses a lookup table to store the action values for the discretized states, artificial neural networks (ANNs) are used as function approximators to output the action values by using the electrical power and rotor speed of the generator as inputs. This eliminates the need for a large storage memory. The proposed method learns the optimal speed control strategy of the WECS by updating the connecting weights of the ANNs, …


Effects Of Droplet Diameter On The Leidenfrost Temperature Of Laser Processed Multiscale Structured Surfaces, Anton Hassebrook, Corey Kruse, Chris Wilson, Troy P. Anderson, Craig Zuhlke, Dennis R. Alexander, George Gogos, Sidy Ndao Jan 2014

Effects Of Droplet Diameter On The Leidenfrost Temperature Of Laser Processed Multiscale Structured Surfaces, Anton Hassebrook, Corey Kruse, Chris Wilson, Troy P. Anderson, Craig Zuhlke, Dennis R. Alexander, George Gogos, Sidy Ndao

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, an experimental investigation of the effects of droplet diameters on the Leidenfrost temperature and its shifts has been carried out. Tests were conducted on a 304 stainless steel polished surface and a stainless steel surface which was processed by a femtosecond laser to form Above Surface Growth (ASG) nano/microstructures. To determine the Leidenfrost temperatures, the droplet lifetime method was employed for both the polished and processed surfaces. A precision dropper was used to vary the size of droplets from 1.5 to 4 millimeters. The Leidenfrost temperature was shown to display shifts as high as 85 ˚C on …


Optimum Renewable Generation Capacities In A Microgrid Using Generation Adequacy Study, Salman Kahrobaee, Sohrab Asgarpoor, Milad Kahrobaee Jan 2014

Optimum Renewable Generation Capacities In A Microgrid Using Generation Adequacy Study, Salman Kahrobaee, Sohrab Asgarpoor, Milad Kahrobaee

Department of Electrical and Computer Engineering: Faculty Publications

Microgrids, as small power systems, may be comprised of different types of loads and distributed generation. As the integration of renewable power generation increases, the total available generation capacity of the system will be more derated due to the effect of equipment failures and the intermittent nature of these resources. Therefore, it is critical to determine optimum renewable generation capacities and provide enough reserve margin to meet the target reliability of the microgrid. In this paper, we first model a microgrid, including conventional and renewable distributed generation and the loads. Second, we determine the renewable generation capacity required to meet …


State Of Charge Estimation Based On A Realtime Battery Model And Iterative Smooth Variable Structure Filter, Taesic Kim, Yebin Wang, Zafer Sahinoglu, Toshihiro Wada, Satoshi Hara, Wei Qiao Jan 2014

State Of Charge Estimation Based On A Realtime Battery Model And Iterative Smooth Variable Structure Filter, Taesic Kim, Yebin Wang, Zafer Sahinoglu, Toshihiro Wada, Satoshi Hara, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes a novel real-time model-based state of charge (SOC) estimation method for lithium-ion batteries. The proposed method includes: 1) an electrical circuit battery model incorporating the hysteresis effect, 2) a fast upper-triangular and D-diagonal recursive least square (FUDRLS)-based online parameter identification algorithm for the electrical battery model, and 3) an iterated smooth variable structure filter (ISVSF) for SOC estimation. The proposed method enables an accurate and robust condition monitoring for lithium-ion batteries. Due to its low complexity, the proposed method is suitable for the real-time embedded battery management system (BMS) application. Simulation and experiment are performed to validate …


Design And Implementation Of A Low-Cost Embedded Linux Gateway For Smart Home Health Monitoring, Mateusz Mittek, Jay D. Carlson, Lance C. Pérez Jan 2014

Design And Implementation Of A Low-Cost Embedded Linux Gateway For Smart Home Health Monitoring, Mateusz Mittek, Jay D. Carlson, Lance C. Pérez

Department of Electrical and Computer Engineering: Faculty Publications

Many wireless sensor network applications require a gateway device to interface with services running on the Internet. Because of the software complexity involved in this device, it is often realized using a real-time operating system running on an application processor. Most systems burden the user with developing the protocol handling and device configuration and management inside the application. In this paper, we present the Angelos Gateway – a turnkey, low-cost, Linux-powered WSN gateway that provides a socket-based environment for rapid network-enabled application development. Experimental results demonstrate that the proposed device is capable of high-throughput packet I/O, confirming the efficacy of …


Automated Indoor Rfid Inventorying Using A Self-Guided Micro-Aerial Vehicle, Steven A. Parkison, Eric T. Psota, Lance C. Pérez Jan 2014

Automated Indoor Rfid Inventorying Using A Self-Guided Micro-Aerial Vehicle, Steven A. Parkison, Eric T. Psota, Lance C. Pérez

Department of Electrical and Computer Engineering: Faculty Publications

A Micro-Aerial Vehicle (MAV) system is presented for automated indoor inventorying using passive radio frequency identification (RFID). This system utilizes a combination of onboard sensing and processing in order to achieve flight stabilization, generate floor maps, and perform path planning. The proposed state estimation method along with a control feedback strategy are demonstrated to be sufficiently accurate for operation in the indoor environment and the proposed path planning technique is shown to be effective for guiding the MAV while it performs automated RFID scanning.


Achieving Robustness And Capacity Gains In Covert Timing Channels, Fahimeh Rezaei, Michael Hempel, Pradhumna Lal Shrestha, Hamid Sharif Jan 2014

Achieving Robustness And Capacity Gains In Covert Timing Channels, Fahimeh Rezaei, Michael Hempel, Pradhumna Lal Shrestha, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, we introduce a covert timing channel (CTC) algorithm and compare it to one of the most prevailing CTC algorithms, originally proposed by Cabuk et al. CTC is a form of covert channels – methods that exploit network activities to transmit secret data over packet-based networks – by modifying packet timing. This algorithm is a seminal work, one of the most widely cited CTCs, and the foundation for many CTC research activities. In order to overcome some of the disadvantages of this algorithm we introduce a covert timing channel technique that leverages timeout thresholds. The proposed algorithm is …


Monitoring Igbt’S Health Condition Via Junction Temperature Variations, Bo Tian, Wei Qiao, Ze Wang, Tanya Gachovska, Jerry L. Hudgins Jan 2014

Monitoring Igbt’S Health Condition Via Junction Temperature Variations, Bo Tian, Wei Qiao, Ze Wang, Tanya Gachovska, Jerry L. Hudgins

Department of Electrical and Computer Engineering: Faculty Publications

Insulated gate bipolar transistor (IGBT) failures are a major issue in modern power electronics applications. Two most dominated failure mechanisms of IGBTs are solder fatigue and bond wire wear-out. This paper proposes a new method to online monitor an IGBT’s health condition by using the instantaneous junction temperature variation between present and the first operating cycles of the IGBT with the same operating current. In this work, the instantaneous junction temperature of an IGBT is estimated from a thermal network model. The proposed method is validated by experimental results obtained from accelerated aging tests for IGBTs.